LS_COLORS/wiki_fileext.md
2018-12-14 09:40:47 +01:00

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Ext. Description Used by

Temporary file Program-dependent format

#24 Printer data file for 24-pin LocoScript matrix printer #IB Printer data file LocoScript #nn Part of file image Long #SC Printer data file LocoScript #ST Standard mode printer LocoScript definitions

$  OS/2 archive file (i.e.         OS/2
     archives$.$$, keys$.$$)
$$$  Temporary file
$?   ZX Spectrum file in HOBETA
     format
$00  Pipe file                       DOS
$DB  Database temporary file         dBase
$O1  Pipe file                       DOS
$VM  Virtual manager temporary file  Windows 3.x
&01,
&02, Holdfast backup archive files   Holdfast
etc
)2(  LHA archiver temporary file     LHA
??$  Backup file                     P-CAD
                                     Expand. Note: ?? could be any first two
                                     characters in a file extension (e.g. BM_
                                     for compressed bitmap (BMP), DL_ for
??_  Microsoft packed file           compressed library, etc.) Files compressed
                                     using this method have been in use on
                                     Microsoft software CDs and floppies since
                                     around 1995.
?DK  Disk image                      Loaddskf.exe
?UT  Nonpacked FTN mail (? - flavor) FidoNet
!qB  Unfinished qBittorrent download qBittorrent
!ut  Unfinished µTorrent download    µTorrent
@@@  DOS 2.0 - 3.2 backup control    DOS commands BACKUP and RESTORE
     file
___  Adinf table                     Adinf
?Q?  Squeeze                         CP/M and MS-DOS
~$~  Temporary file                  1st Reader
     Backup file (name is
~1~, constructed with numbered
~2~, backup option by appending ~,   GNU coreutils (cp, install, ln, mv ),
etc. the incremented number, and     Emacs
     another ~ after the original
     name)
~??  Old Backup files (.MNU to .~MN) Resource Workshop (Borland Delphi)
~H   Cardfile heap                   AZZ Cardfile
μ    Metrowerks Codewarrior project
Π    THINK C project


0      Compressed harddisk data                 DoubleSpace
0B     Printer font with lineDraw extended      PageMaker
       character set
001,                                            FFSJ, HJSplit, JJSplit, split
002,   Split parts of a single whole file       (Unix) (when using numeric
...                                             suffixes)
1      Fax                                      (Many programs)
1      Roff/nroff/troff/groff source for manual cawf2.zip
       page
123    Spreadsheet                              Lotus 1-2-3 version 9 and
                                                version 97
                                                Autodesk 123D design file, a
123dx  CAD drawing file                         ZIP file format package
                                                containing a .sat file and .png
                                                thumbnails.^[1]
15U    Printer font with PI font set            PageMaker
16     SYSLINUX Splash Screen Graphic           SYSLINUX, XnView
1ST    Usually README.1ST text file
1TX    1toX Logipole file
2GR    286 Grabber File                         Win
301    Fax                                      Super FAX 2000 - Fax-Mail 96
386    Intel 80386 processor driver             Windows 3.x
386    Windows virtual device driver            Win
3D     Universal Combat 3D model file           Universal Combat
3DMF   QuickDraw 3D Metafile                    QuickDraw
3DS    3D Studio Graphics format                3D Studio
3DSX   Nintendo 3DS Homebrew File Format        Nintendo 3DS Homebrew Launcher
3DT    Database in which the meta-data of a 3D  3D Topicscape
       Topicscape is held
3DV    3-D wireframe graphics by Oscar Garcia   3dv wireframe viewer
3FX    Effect                                   CorelChart
3G2    Mobile Phone Video
3GA    Mobile Phone Audio (Samsung)
3GP    Mobile Phone Video
3GR    386 Grabber File                         Win
3T4    Binary file converter to ASCII           Util3
4DB    4D Structure File                        4D
4DD    4D Data File                             4D
4DIndy 4D Structure Index File                  4D
4C$    Datafile                                 4Cast/2
4MD    Musical file
4SW    4DOS Swap File                           4DOS
4TH    FORTH source code file                   ForthCMP - LMI Forth
555    16 bit per pixel image file format (5bit Sierra Entertainment
       per component)
       Text (fairly simple format, plain text
602    with binary control commands embedded    Text602 text processor by
       within text lines and special formatting Software602
       commands on dedicated lines)
668    Music (the mixing is always at 12048 Hz)
669    Music (8 channels)                       The 669 Composer
6CM    Music (6 Channel Module)                 Triton FastTracker
75     75×75 dpi display font                   Ventura Publisher
       A compressed archive file format that
7z     supports several different data          7-Zip
       compression, encryption and
       pre-processing algorithms
8      A86 assembler source code file
85     85×85 dpi display font                   Ventura Publisher
8BF    Adobe Photoshop compatible filters/
       plugins
8BI    Adobe Photoshop compatible filters/
       plugins
8BX    Adobe Photoshop compatible filters/
       plugins
890    ScanTitling subtitle files
8CM    Music (8 Channel Module)                 Triton FastTracker
8M     Printer font with Math 8 extended        PageMaker
       character set
8U     Printer font with Roman 8 extended       PageMaker
       character set
83p    Executable program for TI-83 Graphing    TI Connect
       Calculator
89p    Executable program for TI-89/89 Titanium TI Connect
       Graphing Calculator
8xp    Executable program for TI-83/84 Plus     TI Connect
       Graphing Calculator
91     91×91 dpi display font                   Ventura Publisher
96     96×96 dpi display font                   Ventura Publisher

A           ADA source code file
A           Library                                  Unix
A##         AlZip Compressed Files' pieces
A11         Graphics AIIM image file
A2W         World file for Alice programming         Alice 2
            language, version 2
A3P         Project file for Alice programming       Alice 3
            language, version 3
A80         Assembler language source for 8080
AA, AB, ... Split parts of a single whole file       split (Unix)
            Advanced Audio Coding, a standardized,
AAC         lossy compression and encoding scheme
            for digital audio
AAF         AutoPatcher file
            Advanced Authoring Format, an advanced
AAF         media wrapper file for professional
            applications
AAS         Animation Play Script                    AAPlay
AB          Android adb Backup                       adb
AB6         Datafile                                 ABStat
AB8         Datafile                                 ABStat
                                                     Many Computer Graphics
ABC         Alembic - 3D geometry / models           tools, see Alembic
                                                     (Computer Graphics) for a
                                                     list.
ABC         Document                                 ABC FlowCharter 1.0
ABC         Music in ABC format                      Mainly Video Games
ABP         Data                                     ABComp compressed
ABP         AVS Barcode Profile                      AVS Barcode Source
ABF         Adobe Binary Screen Font                 Adobe Systems Software
ABK         Automatic backup file                    CorelDRAW
ABM         Image PALS album file
ABM         Album file (various programs)
ABR         Adobe Brush file for PhotoShop           PhotoShop
ABS         Abstracts (info file)
ABS         Data file                                Abscissa
AC          Project backup                           Audit Command Language
                                                     (ACL)
ACA         Project                                  Project Manager Workbench
ACB         Archive                                  ACB
ACB         see ACMB
ACC         Program (DR-DOS - ViewMax)               GEM / resident
ACCDA       Data                                     Microsoft Access Database
                                                     Wizard (Open XML)
ACCDB       Data                                     Microsoft Access Database
                                                     (Open XML)
ACCDE       Data                                     Microsoft Access Database
                                                     Wizard (Open XML)
ACCDT       Data                                     Microsoft Access Database
                                                     Template (Open XML)
ACCDU       Data                                     Microsoft Access Database
                                                     Wizard (Open XML)
ACCFT       Microsoft Access Data Type Template^[1]  Microsoft Access
ACDC        layered graphics file                    ACDSee
ACDA        ACDSee Action                            ACDSee
ACDAPK      ACDSee Actions Pack                      ACDSee
ACE         Archive                                  ACE
ACF         Adobe Custom Filter for PhotoShop        PhotoShop
ACL         Project                                  Audit Command Language
                                                     (ACL)
ACL         AutoCorrect List                         Microsoft Office
ACM         Audio Compression Module add-on          Win
ACMB        Graphics file
ACO         Adobe Color Palette                      Adobe
ACT         ACTOR source code file                   ACTOR
ACT         Animations Works Actor (Graphics cell)   Animation Works
ACT         FoxDoc Action Diagrams                   FoxPro
ACT         Presentation                             Action!
AD          AfterDark screensaver module             AfterDark
AD2         ADPCM 2-bit compressed voice file        ZFAX
AD3         ADPCM 3-bit compressed voice file        ZFAX
ADA         Ada source code file
ADB         Ada Package Body
ADC         Bitmap graphics (16 colors)              Scanstudio
ADC         Dictionary                               Lingvo
ADD         OS/2 adapter device driver
ADEF        Legato Application Definition            Legato.io build tools
                                                     mkapp and mksys
ADF         Amiga Disk File                          unADF, UAE, WinUAE etc...
ADG         Data                                     ADG 3D Scene
ADI         Graphics file                            AutoCAD
ADI         Database Index File                      Advantage Database Server
ADICHT      LabChart data acquisition file           ADInstruments
ADL         MCA adapter description library          QEMM
ADL         ADONIS Definition Language file for      ADONIS
            exporting models and model groups
ADM         After Dark support file                  AfterDark
ADM         ADEM file format                         ADEM
ADI         Database Memo File                       Advantage Database Server
ADN         Add-in                                   Lotus 1-2-3
ADR         After Dark support file                  AfterDark
ADS         Ada Package Specification
ADSON       Adsonica sound and image file            Adsonica
ADT         WoW geographical map location file       Blizzard Entertainment
                                                     games (various)
ADT         Datafile for cardfile application        HP NewWave
ADT         Abrechnungsdatentransfer, an xDT         Healthcare providers in
            application                              Germany
ADT         Dictionary                               Lingvo
ADT         Fax                                      AdTech
ADI         Database Table                           Advantage Database Server
ADV         GUS device driver                        Gf166.com
ADX         Document                                 Archetype Designer
ADZ         Amiga Disk Zipped (See Amiga Disk File)  GZip
AEP         After Effects Project File               Adobe After Effects
            File encrypted using the Advanced        AES Crypt (Windows, Mac,
AES         Encryption Standard (AES)                Linux, Java) and Crypt4All
                                                     (Android)
AF2         Flowchart                                ABC FlowCharter 2.0
AF3         Flowchart                                ABC FlowCharter 3.0
AFI         Truevision bitmap graphics
AFL         Font file (for Always)                   Lotus 1-2-3
AFM         Datafile for cardfile application        HP NewWave
AFM         Type 1 font metric ASCII data for font   ATM - many
            installer
AFP         Shape palette                            ABC FlowCharter
AFT         Template                                 ABC FlowCharter 3.0
AFW         Workplace                                ABC FlowCharter 3.0
AGR         ArcView ASCII grid
AHK         AutoHotkey script file                   AutoHotkey
AI          Adobe Illustrator Artwork                Adobe Illustrator
AIF         see AIFF
AIFC        Audio Interchange File Format with
            Compression
AIFF        Audio Interchange File Format            Convert (c) Villena
AiM         Asm Text Mode Image File                 The Ultimate Draw
AIN         Archive                                  AIN
AIN         Job schedule                             AutoIntern
AIO         APL programming language file transfer
            format file
AIR         Adobe AIR installation package           The Adobe AIR runtime
                                                     environment
AIS         Array of Intensity Samples graphics file Xerox
AIX         Datafile for cardfile application        HP NewWave
                                                     Akai S5000 and S6000
AKM         "Akai Multitimbral" sample information   hardware samplers (MS-DOS
            file                                     -based) and compatible
                                                     software samplers
                                                     Akai S5000 and S6000
AKP         "Akai Program" sample information file   hardware samplers (MS-DOS
                                                     -based) and compatible
                                                     software samplers
ALC         Molecular coordinates                    Alchemy, RasMol
ALG         Activity Log                             ARCSOLO
ALG         ER Mapper Algorithm                      ERViewer
ALE         Avid Log Exchange (used in film & video  Avid
            editing)
ALL         Arts & Letters symbol and font files     Arts & Letters
ALL         Filelist w/ all files                    FRQView
ALL         Format file for working pages            Always
ALL         General printer information              WordPerfect for Win
ALO         Almanac support file
ALT         Menu file                                WordPerfect Library
ALZ         AlZip Compressed Files
AMD         Maxum chromatograph offline database     Siemens Maxum
                                                     Chromatograph
AMF         Music (Advanced Module Format)           DMP
AMF         Additive Manufacturing File Format       Computer Aided Design
                                                     Software
AMG         Archive                                  AMGC
AMG         System image file                        ACTOR
AML         AutomationML                             AutomationML Group
AMLX        Compressed and packed AutomationML file  AutomationML Group
AMPL        AMPL source code file                    AMPL
AMR         Audio format for mobile phones (Nokia,
            SonyEricsson)
AMS         Adobe Monitor Setup calibration file     PhotoShop
AMS         Music format
ANI         Animation cursors for Win                Win95 - WinNT
ANI         Animation                                IconAuthor
ANM         Animation                                Deluxe Paint Animator
            Trainz Animation specification file, for
ANIM        example a steam locomotive's connecting  Trainz/Auran JET files
            rod movements, or water movement on a
            river or lake motion. (Obsolescent)
ANN         Annotations of old Windows Help file     Windows 3.0 - XP
Ann         Multi volume ARJ archive                 ARJ
ANS         ANSI character graphics (animation) file ANSView
ANS         ASCII text ANSI character set            NewWave Write
AOL         America On-line for Windows DLL          Win
AOS         Add-On Software                          Nokia 9000
AP          Archive                                  WHAP
AP          Datafile                                 Datalex EntryPoint 90
APC         Printer driver                           Lotus 1-2-3
APD         Printer driver                           Lotus 1-2-3
APE         Monkey's Audio (Lossless)                audio media players
APF         Printer driver                           Lotus 1-2-3
API         Adobe Printer Ink file for PhotoShop     PhotoShop
API         Passed parameter file                    1st Reader
API         Printer driver                           Lotus 1-2-3
APK         Android Application                      Android
APL         APL work space format file
APL         Support module used by Manugraphics APL
            products
APL         EV-Dos Application File
APL         ACDSee plugin                            ACDSee
APM         Authorware Macintosh                     Authorware
APP         Add-in application file                  Symphony
APP         Application object file                  dBASE Application
                                                     Generator
APP         Application                              FoxPro
APP         Application and Application Bundle       Mac OS X
APP         Executable workflow / macro file         Automator
APP         Executable application file              DR-DOS - NeXTstep - Atari
APP         Generated application                    FoxPro
APPLICATION ClickOnce Application Deployment         Microsoft Windows
            Manifest
APR         Employee performance review              Employee Appraiser
APW         Authorware Windows                       Authorware
APX         Appexpert database file                  Borland C++ 4.5
AQF         Analyzer Queries and Filters             Actix
AR          Argon - for 3D Modeling                  Ashlar-Vellum
AR7         Archive                                  AR7
ARC         Archive                                  ARC - PKARC/PKXARC - PKPAS
                                                     - PKUNPAK - QUARK
ARC         Archive                                  SQUASH
ARC         Nintendo proprietary archive format      Various Nintendo games
ARD         Map                                      Holux - Alan
ARF         Automatic Response File
ARH         Archivers definitions file               DN
ARI         Archive                                  ARI
ARJ         Archive                                  ARJ - ARJZ
ARK         ARC archive                              CP/M port of ARC file
                                                     archiver
ARK         Archive                                  QUARK
ARK         Managing your Money Archive File
ARR         Arrangement                              Atari Cubase
ART         Gerber artwork                           Cadence Allegro
ART         First Publisher, Designworks,            All GST/Greenstreet Draw
            Greenstreet Draw graphic file            products
ART         Graphics (scrapbook)                     Art Import
ART         Graphics format (Another Ray Tracer)     PFS:1st publisher - Art
                                                     Import
ARTX        file format                              Artisteer
ARTX        file format                              belightsoft Text Art
ARX         Archive                                  ARX
ASC         ASCII text file
ASC         Transport armor file                     PGP
ASD         Autosave file                            Microsoft Word
ASD         Presentation                             Astound
ASD         Screen driver                            Lotus 1-2-3
ASD         Spectral Data Set                        ASD Inc. RS3 spectral
                                                     acquisition program
ASE         Velvet Studio Sample                     AWAVE
ASE         ASCII Scene Export                       3D Studio
ASF         Datafile (APL Shared File)               STATGRAPHICS (APL*Plus/PC)
ASF         Screen font                              Lotus 1-2-3
ASF         Advanced Streaming Format (Compressed    Microsoft Corporation
            Windows audio/video)
ASK         SYSGEN answer file                       RT-11
ASH         Assembly language header file            TASM 3.0
ASI         ASIC language source                     ASIC
ASI         Assembler include file                   Turbo C - Borland C++
ASM         Assembler language source                TASM, MASM, NASM, Yasm,
                                                     FASM
ASMX        ASP.NET Web Service                      Microsoft Corporation
ASO         Assembler object (object-oriented) file  Turbo Assembler
ASP         ASPECT source code file                  Procomm Plus
ASP         Association of Shareware Professionals
            OMBUDSMN.ASP notice
ASP         Active Server Pages of Microsoft.Net     Microsoft Corporation
ASPX        ActiveX Server Pages of Microsoft.Net    Microsoft Corporation
ASS         Amalgam Scene Specification              Halo 2 Map Editor
ASS         Advanced SubStation Alpha (Subtitles)
AST         Adobe Color Separation table for         PhotoShop
            PhotoShop
AST         Nintendo proprietary music streaming     Various Nintendo games
            format
ASV         Autosave File                            MATLAB
ASW         Authorware Star                          Authorware
ASX         Advanced Stream Redirector file,         Microsoft Corporation
            redirects to an ASF file (see ASF)
ASZ         Skin                                     AltDesk
AT2         Auto template                            Aldus Persuasion 2.0
                                                     All Sony devices and
AT3         Atrac 3 Sound/music file                 programs with the Atrac 3+
                                                     specification
ATM         Adobe Type Manager data/info
ATML        Awhcp HTML file
ATN         Adobe Photoshop action                   Adobe Photoshop
ATT         AT&T Group                               GCGW
ATTF        AramOS TypeAtor Text File                AramOS TypeAtor 1.0
                                                     (Development State)
ATY         Produced when an association type is     3D Topicscape
            exported by 3D Topicscape
AU          Sun/NeXT/DEC Audio file                  AWAVE, GoldWave
AU          Sound (audio) file                       Sun Microsystems - Convert
                                                     (c) Villena
AUD         Audio file                               AudioRack
AUP         Audacity project file                    Audacity
AUS         Kedit AutoSave file                      Kedit
AUX         Auxiliary dictionary                     ChiWriter
AUX         Auxiliary references                     TeX/LaTeX
AUZ         Ableton Live File                        Authorization File for
                                                     Ableton Live
AVA         Publication                              Avagio
AVB         AntiViral Toolkit Pro Bases
AVI         Audio Video Interleaved animation file   Video for Windows
AVR         Audio Visual Research                    AWAVE
AVS         Audio Video Software                     AVS Video Editor (video
                                                     editing software)
AVT         AVATAR-coding files                      A3E
AW          Text file                                HP AdvanceWrite
AW          Proprietry Nintendo wave format          Various home console
                                                     Nintendo games
AWA         Animations Works Accelerated Movie       Animation Works
AWD         Microsoft Fax At Work Document           Microsoft Fax At Work
AWK         AWK script/program                       awk, GNU Awk, mawk, nawk,
                                                     MKS AWK, Awka (compiler)
AWM         Animations Works Movie (as .AVI)         Animation Works
AWS         Data (APL Workspace)                     STATGRAPHICS (APL*Plus/PC)
Ax          Directshow filter file format
AXF         ARM Executable Image generated by the
            ARM tools
AXF         "lightweight geodatabase" [1]            ESRI ArcPad
AXM         Axmedis object                           Axmedis Tools
AZD         Amazon Software Download                 Amazon Software Download
AZW         DRM enabled eBook                        All models of Amazon
                                                     Kindle
AZW1        DRM enabled eBook with embedded fonts    All models Amazon Kindle
AZW2        Program file                             All models of Amazon
                                                     Kindle excluding Kindle 1
AZZ         Data file                                AZZ Cardfile
ATSOFTS     Encrypted File                           ^[2]LetEncrypt.xyz

B1      Archive file format                      B1 Free Archiver
B&W     Black and white graphics file            atari - mac
B&W     Mono binary screen image                 1st Reader
B       Batch list                               APPLAUSE
B       Grand Theft Auto saved game              Any of the 3D Grand Theft Auto
                                                 games in either III or IV era.
B_W     Black and white graphics file            Atari - mac
B1N     Both mono and color binary screen image  1st Reader
B30     Printer font (JLaser - Cordata)          Corel Ventura Publisher
B3D     Blitz3D files                            Blitz3D
B8      Raw graphics file (one byte per pixel)   PicLab
        plane two
                                                 Scifer Archiver and
BA      Binary Archive                           Compression [External Header
                                                 Mode]
BAC     Compiled BASIC                           RT-11 BASIC-11
BAD     Bad file                                 Oracle Corporation - many
BAD     Animation file                           Novalogic
BAD     File which covers bad blocks on disk     RT-11
        volume (not to be moved)
BAK     Backup file
BAL     Music score                              Ballade
BALANCE Balance accounting sheet file            Balance
BAP     Blaze Audio Wave Information File        BlazeAudio MadCap Software
BAR     Horizontal bar menu object file          dBASE Application Generator
BAR     Info Bar for GFX2EXE                     GFX2EXE
        Broker Archive. Compressed file
BAR     containing number of other files for     IBM WebSphere Message Broker
        deployment.^[3]
BAS     BASIC language source                    QuickBASIC - GW-BASIC -
                                                 FreeBASIC
BAT     Batch file                               MS-DOS, RT-11
BB      Database backup                          Papyrus Design Group
BBL     Bibliographic reference file             TeX/BibTeX
BBM     Brush                                    Deluxe Paint
BBP     Playlist                                 BassBox
BBQ     BitBeamer Transfer Queue file            BitBeamer
BBS     Bulletin Board System announce or text
        info file
BBS     Hudson-style messagebase                 FTN software
BC!     Unfinished download                      Unfinished BitComet download
                                                 (a BitTorrent client)
BCD     Boot Configuration Data                  Windows Vista and later,
                                                 Registry Editor
BCF     Card data                                Bingo Card Creator
BCH     Batch process object file                dBASE Application Generator
BCH     Datafile                                 Datalex EntryPoint 90
BCO     Outline font description                 Bitstream Inc.
BCP     Borland C++ makefile
BCT     Backup dictionary                        Clarion
BCW     Environment settings                     Borland C++ 4.5
BDB     Bookends database                        Bookends
BDC     Dictionary                               Lingvo
BDEF    Builder Definition                       Websphere Portlet Factory
BDF     Adobe Glyph Bitmap Distribution Format   Adobe Software
BDF     Binary update file                       BUPDATE.EXE (c) TNT Techn.
BDF     Bitmap Distribution Format font file     X11
BDF     Datafile                                 Egret
BDIC    Google Chrome Dictionary                 Google Chrome
BDM     Videoclip                                AVCHD
BDMV    Blu-ray Video Data Content file          Media players / software that
                                                 supports Blu-ray structure
BDR     Border                                   Microsoft Publisher
BDT     Dictionary                               Lingvo
BDT     Behandlungsdatentransfer, an xDT         Healthcare providers in
        application                              Germany
BEAM    Executable bytecode file in fat binary   BEAM (Erlang virtual machine)^
        format                                   [4]
BEF     Bleck Encrypted File
BEM     BIM Cost estimating file                 BIMestiMate
BEZ     Outline font description                 Bitstream
BF      Brainfuck sourcefile
BF2     Bradford 2 font
BFC     Briefcase Win95                          Win95
BFM     Font metrics                             unix/Frame
BFS     Binary File Storage
BFX     Fax                                      BitFax
BGA     Bitmap graphics
BGI     Borland Graphics Interface device driver Turbo C - Turbo Pascal
BH      Blackhole                                data compression format
BI      BASIC include file                       Visual Basic - FreeBASIC
BIB     Bibliography (ASCII)
BIB     Database - not compatible with TeX       Papyrus
        format
BIB     Literature database                      TeX/BibTeX
BIF     Binary Image Format b&w graphics file    Image Capture board
BIK     Bink Video file (RAD Video)
BIM     Building Information Modeling            ArchiCAD / Autodesk Revit
BIN     Binary file, usually zero-start (.com
        analog)
BIN     SGI Powerflip
BIN     Text mode memory dump                    The Draw - TUD - ACiDDraw -
                                                 etc.
BIO     BioniX Wallpaper playlist file           BioniX Wallpaper Changer
BIO     OS/2 BIOS
BIT     Bitmap X11
BIT     Encrypted file                           FinalCrypt
BK!     Document backup                          WordPerfect for Win
BK      Faxbook                                  JetFax
BK?     Backup file
BKC     Backup catalog                           Backup4all
BKF     Backup archive                           Windows NTBackup Utility
BKn     Timed backup file for document window n  WordPerfect for Win
BKP     Backup file                              Write - TurboVidion
                                                 DialogDesigner
BKW     Mirror image of font set                 FontEdit
BLD     BLoaDable picture                        BASIC
BLD     SYSGEN Build procedure file              RT-11
BLEND   Blender3D Project File                   Blender
BLG     Backup Log                               ARCSOLO
BLK     Temporary file                           WordPerfect for Win
BLOB    Unknown                                  Steam (software) for Win
BLP     Blizzard Game Picture                    Blizzard Entertainment games
                                                 (various)
BM      BitMap graphics file
BM3     UIQ3 Phone backup
BMD     Nintendo proprietary 3D model file       Various Nintendo games
BMK     Bookmark of old Windows Help file        Windows 3.0 - XP
BMP     OS/2 or Win graphics format (BitMap      QPeg - CorelDraw - PC
        Picture)                                 Paintbrush - many
BMPW    bitmap world-file - geo-references info
BMS     Nintendo proprietary MIDI tracker format Various Nintendo games
BMT     Ami Pro Button                           Ami Pro
BNA     Data                                     Atlas Boundary
BNK     Adlib instrument bank file
BNR     Graphics Banner                          Banner - Poster
BOB     File archive for Lego Island 2           Lego Island 2
BOD     Stores paths to game files in a BOB      Lego Island 2
        archive
BOK     Shamela Library book                     Shamela Library Program
BOO     Book-format                              READIBM
BOO     Compressed file ASCII archive created by msbooasm.arc
        BOO (msbooasm.arc)
BOO     Boo programming language source file     Boo Programming Language
BOT     Bot files, these go with JKB files       Quake 3 Engine
BPC     Chart                                    Business Plan Toolkit
BPOLY   Data                                     Prisms binary 3D object
BPP     Backup application                       Clarion
BPS     Used for game patches                    FLIPS and other patch
                                                 implementers
BPS     WPS backup file^[5]                      Microsoft Word, Microsoft
                                                 Works
BPS     Binary file commonly used in computer    Certain antivirus programs and
        malware                                  computer malware
BPT     Bitmap fills file                        CorelDRAW
BPW     Bitser proprietary encrypted password    Bitser password manager
        file
BR      Script                                   Bridge
BRD     EAGLE board file                         EAGLE
BRD     Tanzzle board file                       Tanzzle
BRD     Cadence Allegro board file               Cadence
BRF     Braille                                  Braille embossers and
                                                 refreshable displays
BRK     Fax                                      Brooktrout Fax-Mail
BRK     The Brake! Mailer REXX script            The Brake!
BRL     CAD                                      Ballistic Research Laboratory
                                                 CAD
BS      Boot sector file                         SYSLINUX
BS2     Archive                                  BS2.EXE
BSA     Archive                                  BSArc
BSC     Compressed Apple II file archive created BINSCII
        by BINSCII
BSC     Database                                 Source Browser
BSC     Pwbrmake object file                     Microsoft Fortran
BSP     GoldSource/Source engine map files       Valve Corporation
BSP     id Tech map files                        id Software
BSS     boot sector (DOS) file                   SYSLINUX
BSS     Casio Phone base                         PC-LINK
BST     BiblioTex file (BiblioTex=bibliography   TeX
        file)
BSY     Busy flag                                FTN soft
BTM     Batch-to-memory (quick batch)            4dos -ndos
BTN     Makeover Button file
BTX     backup of 4DOS batch files (_4INST.BTM)  4DOS
BUFR    Binary Universal Form for the
        Representation of Meteorological Data
BUG     Bugs and Problems
BUN     LucasArts Bundle File
BUP     Backup file
BUT     Button definitions                       Buttons!
BUY     Datafile format                          movie
BVF     BIM model file format                    BIM Vision
BVn     Overflow file below insert point in Doc  WordPerfect for Win
        n
BWB     Spreadsheet application                  Visual Baler
BWR     Beware (buglist)                         Kermit
BYK     BYK Compressed File                      BYK
BYU     BYU Movie                                BYU
BZ2     Archive                                  bzip2
BZM     Map                                      Blitzkrieg
BZN     Map file                                 Star Trek Armada II Fleet
                                                 Operations map file

C--        C-- language source                           Sphinx C--
           C language source
                                                         Watcom C/C++, Borland
C          Note that on case-sensitive platforms like    C/C++, gcc and other C
           Unix and with the gcc compiler the uppercase  compilers
           .C extension indicates a C++ source file.

C          Unix file archive                             COMPACT
C++        C++ language source
C00        Print file                                    Ventura Publisher
C01        Typhoon wave files                            AWAVE
C32        COMBOOT Executable (32-bit)                   SYSLINUX
C86        C source code file                            Computer Innovation
                                                         C86
CA         Initial cache data for root domain servers    Telnet
CA?        Borland packed and split file                 Borland Installer
CAB        Cabinet archive                               Windows 95 and later,
                                                         many file archivers
CAC        dBASE IV executable when caching on/off (see
           cachedb.bat)
CAD        Drawing                                       BobCAD-CAM
CAD        Document                                      Drafix Windows CAD
CAL        Calendar file                                 Windows 3.x
CAL        Spreadsheet format                            SuperCalc
CALS       Computer Aided Acquisition and Logistics
CALS       Support Raster Format
CAM        Casio Camera
CAN        Fax                                           Navigator Fax
CAP        Caption                                       Ventura Publisher
CAP        Capture file                                  ProComm - Telix
CAS        C + ASM language source                       Turbo C
CAT        Catalog                                       CP Backup - dBASE IV
CAT        Device driver digital signature               Microsoft Windows
CAT        Stellarium Star Catalogue                     Stellarium
CATDrawing Drawing file of CATIA V5                      CATIA V5
CATPart    Part file of CATIA V5                         CATIA V5
CATProduct Assembly file of CATIA V5                     CATIA V5
CATS       Combined source                               ATS
CBA        Source code                                   Creative BASIC
CBC        Fuzzy logic system                            CubiCalc
CBL        COBOL source code file
CBM        Compiled bitmap graphics                      XLib
CBR        Comic Book Reader (RAR file)                  CDisplay and similar
CBS        MasterWord button bar configuration file
CBT        COMBOOT Executable (incompatible with DOS COM SYSLINUX
           files)
CBT        Computer Based Training                       many
CBZ        Comic Book Reader (ZIP file)                  CDisplay and similar
CC         C++ source code file
CC         CC language source                            CC
CCC        Bitmap graphics (native format)               Curtain Call
CCD        text metadata for CD/DVD images               CloneCD Control File
CCF        Communications configuration file             Symphony
CCF        Color Chat file                               Color Chat File
CCH        Chart                                         CorelChart
CCITT      CCITT Group 3 and Group 4 Encoding
CCL        Communication Command Language file           Intalk
CCO        BTX Graphics file                             XBTX
CCT        Print Template                                BobCAD-CAM
CD         CD description                                DN
CDA        CD-Audio                                      Win95
CDB        Card database                                 CardScan
CDB        Main database                                 TCU Turbo C Utilities
CDF        Common Data Format
CDF        Company Data File                             Nominal Small Business
                                                         Accounting software
CDF        Computable Document Format                    Mathematica
CDF        Cyberspace Description Format
CDF        Graphics                                      netcdf
CDK        Document                                      Atari Calamus
CDL        CADKey CADL Language                          CADKey
CDM        Disk Drivers NPA                              Novell NetWare
CDM        Music format (compressed)
CDO        Music notation                                Cc,rrescendo Music
                                                         Notation Editor
CDR        Vector graphics format (drawing)              CorelDraw!
CDT        Corel Draw Template File                      CorelDraw!
                                                         Visual FoxPro,
CDX        Compound index file                           Advantage Database
                                                         Server
CE         Computer Eyes                                 Conversion Artist
CE         Main.ce                                       The FarSide Computer
                                                         Calendar
CEB        Cont. Edge Bitmap                             Conversion Artist
CEF        CA-Clipper Workbench Application              CA Clipper
CEF        Export File
CEF        Compact Embedded Font                         Adobe Illustrator
                                                         Tempra Show - Edsun
CEG        Bitmap graphics                               Continuous Edge
                                                         Graphics
CEL        Animation CEL                                 3D Studio
CEL        Graphics                                      Autodesk Animator -
                                                         Lumena
CEL        Celestia Script                               Celestia
CELX       Celestia Script                               Celestia
CER        Security certificate                          Microsoft Windows
CF         Configuration file                            imake
CFA        Audio file                                    Adobe Premiere Pro
CFC        ColdFusion Component                          Adobe ColdFusion
CFG        Configuration file
CFL        Chart                                         CorelFLOW
CFM        ColdFusion Markup Language                    Adobe ColdFusion
CFN        Font data                                     Atari Calamus
CFO        C Form Object internal format object file     TCU Turbo C Utilities
CFP        Fax                                           The Complete Fax
                                                         Portable
CFT        CFast graphics file                           Disney Animation
                                                         Studio
CGA        CGA display font                              Ventura Publisher
CGI        Common Gateway Interface script
CGM        Computer Graphics Metafile vector graphics    A&L - HG - many
CH         Clipper language header                       CA Clipper
CH3        Chart                                         Harvard Graphics 3.0
CH4        Presentation                                  Charisma 4.0
CHD        Font descriptor                               FontChameleon
CHI        ChiWriter Document                            ChiWriter - Chiview
CHK        Recovered data                                DOS CHKDSK
CHK        Temporary file                                WordPerfect for Win
CHL        Configuration History Log
CHM        Compiled Help File                            Microsoft Windows,
                                                         Help Explorer Viewer
                                                         Krasbit Technologies,
CHML       Encrypted Data File                           Chameleon Imaging
                                                         Workflow Software
CHN        Data                                          Ethnograph 3
CHO        ChordPro lead sheet (lyrics and chords)       ChordPro and similar
                                                         tools
CHP        Chapter file                                  Ventura Publisher
CHR        Character set                                 Turbo C - Turbo Pascal
CHT        Chart                                         Harvard Graphics 2.0 -
                                                         SoftCraft Presenter
CHT        CHeaT in any program/game                     many
CHT        Interface file for ChartMaster                dBASE
CHZ        Archive                                       CHARC
CIA        Nintendo 3DS importable archive               Nintendo 3DS
CIF        Caltech Intermediate Format graphics file
CIF        Chapter information                           Ventura Publisher
CIF        Crystallographic Information File             RasMol, Jmol
CiM        C Text Mode Image File                        The Ultimate Draw
CIX        Database index                                TCU Turbo C Utilities
CKB        Borland C++ 4.x editor keystroke mapping      BCW.EXE
CL         OpenCL kernel code
CL         COMMON LISP source code file
CLA        Source                                        Clarion
CLASS      Java class file                               Java
CLD        Clipper debugger configuration file           CA Clipper
CLJ        Clojure source code                           Clojure
CLP        Clip art graphics file                        Quattro Pro
CLP        Clipboard file                                Windows 3.x
CLP        Compiler response file                        CA Clipper
CLP        Graphics format                               PCPAINT/Pictor
                                                         Media hardware /
CLPI       ClipAV Clip Information file for Blu-ray      software with Blu-ray
                                                         structure support
CLPRJ      ClassicLadder project file                    ClassicLadder
CLR        Color binary screen image                     1st Reader
CLR        Color definitions                             Photostyler
CLR        Color scheme                                  Boxer/2
CLR        Palette file for GIS format
CLS        C++ class definition file
CLW        MFC Class Wizard information                  Microsoft VC++
CM         Data file                                     CraftMan
CMB        Xtree for Windows Button Bar file
CMD        Command                                       dBASE - Waffle
                                                         Microsoft Windows NT
CMD        Command Prompt batch file                     based operating
                                                         systems
CMD        executable programs                           CP/M-86 operating
                                                         system
CMD        External command menu                         1st Reader
CMD        OS/2 batch/REXX file                          OS/2
CMF        FM-music file (Creative Music File)
CMK        Card                                          Card Shop Plus
CMM        CMM script (batch) file                       CEnvi
CMOD       Celestia Model                                Celestia
CMP        Bitmap graphics (Lead CMP compression)
CMP        Compressed data                               PKWare Inc. data
                                                         compression library
CMP        Header file for PostScript printer files      CorelDRAW
CMP        Photofinish Calibration Map                   Photofinish
CMP        User dictionary                               Microsoft Word for DOS
CMR        Coach 7 project file                          Coach 7
CMRL       Concise message routing language              DOTGO
CMS        Content Management System                     Any Web Browser
CMU        Carnegie Mellon University Formats
CMV        Animation (CorelMove CorelDraw 4.0)           CorelMove CorelDraw
                                                         4.0
CNC        CNC general program data
CND        System generation conditional file            RT-11
CNF        Configuration (program - printer setup)       program - printer
                                                         setup
CNF        Configuration file
CNT        contents table of old Windows Help file       Windows 3.0 - XP
CNV        Temporary file                                WordPerfect for Win
CNV        Winword DLL used as part of an import         Microsoft Word
           operation (CNV=converter)
CO         Cobalt - parametric drafting and 3D modeling  Ashlar-Vellum
COB        Calgari trueSpace2 File Format
COB        COBOL source code file
COD        Code definition table                         UUPC
                                                         Forecast Plus -
COD        Datafile                                      Microsoft Multiplan -
                                                         StatPac Gold
COD        file including CODES for any program/game     many
COD        Printer code definition file                  Boxer/2
COD        Program compiled code                         FORTRAN
COD        Template source file                          dBASE Application
                                                         Generator
COD        Videotext file
COE        Coefficient file                              Xilinx ISE
COF        Animation Control File                        Diablo II
COFFEE     CoffeeScript source code file
COL        Color palette                                 Autodesk Animator -
                                                         many
COL        Spreadsheet                                   Microsoft Multiplan
COL        DIMACS graph data stores a single undirected
           graph (text and binary variants)
COM        Command (memory image of executable program)  DOS
COM        Indirect command file (sequence of commands   RT-11
           to be executed)
CON        Configuration file                            Simdir
CON        MSTS Consist file                             MSTS
CONTACT    Contact file                                  Windows
CPC        Compressed image                              Cartesian Perceptual
                                                         Compression
CPD        Script                                        Complaints Desk
CPF        Fax                                           The Complete Fax
CPI        ColorLab Processed Image bitmapped graphics
           file
CPI        MS-DOS codepage file                          MODE.EXE
CPI        Video clip information file                   The AVCHD format
CPL        Control panel file                            Windows 3.x
CPL        copley file                                   COPLEY.EXE (Copley
                                                         Scientific Ltd)
CPL        Presentation                                  Compel
CPMZ       ConPro/Miradi Zipfile                         Miradi and ConPro
CPP        C++ language source                           Watcom C/C++
CPP        Presentation                                  CA-Cricket Presents
CPR        Knowledge Access                              GCGW
CPR        Cubase Project File                           Steinberg Cubase
CPS        backup of startup files by QEMM (?)
           autoexec.cps
CPT        Encrypted memo file                           dBASE
CPT        Mac file archive                              COMPACT PRO
CPT        Template                                      CA-Cricket Presents
CPZ        Music text file                               COMPOZ
CR2        Raw image format                              Canon digital cameras
CRA        Advanced crack file (usually text)
CRD        Cardfile                                      Windows 3.x - YourWay
CRD        Map                                           Holux - Alan
CRD        Molecular coordinates                         CHARMM, RasMol
CRDOWNLOAD Google Chrome download in progress            Google Chrome
                                                         Microsoft MASM -
CRF        Cross-reference                               Zortech C++, RT-11
                                                         CREF
CRK        Crack file (usually text)
CRP        Encrypted database                            dBASE IV
CRS        File Conversion Resource                      WordPerfect 5.1
CRT        Security certificate                          Microsoft Windows
CRT        Terminal settings information                 Oracle
CRU        Compressed file archive created by CRUSH
CRW        CrossWords document file
CRX        Google Chrome Extension                       Google Chrome
CS         C# source file                                C#
CSD        Compact Shared Document                       Dream To Reality
CSG        Batch file (Submit)                           ISIS/w
CSG        Graph                                         Statistica/w
CSHTML     Razor page/view
CSM        Borland C++ 4.x precompiled header file       BCW.EXE
CSO        ACDSee edit tool                              ACDSee
CSP        PC Emcee Screen Image file                    Computer Support
                                                         Corporation
CSS        Datafile                                      CSS - Stats+
CSS        Datasheet                                     Statistica/w
CSS        cascading style sheet
CSV        Adjusted EGA/VGA palette                      CompuShow
CSV        Comma Separated Values text file format
           (ASCII)
CTC        Control file                                  PC Installer
CTF        Character code translation file               Symphony
CTK        CommonTime Key file                           CommonTime software
                                                         applications
CTL        Control file                                  dBASE IV - Aldus Setup
CTL        BATCH control file (generated by BATCH from   RT-11
           .BAT file)
CTT        BATCH Temporary file                          RT-11
CTX        Ciphertext file                               Pretty Good Privacy
                                                         RSA System
CTX        Course TeXt file                              some Microsoft online
                                                         guides
CTX        document                                      Creativyst Table
                                                         eXchange
CUE        Cue sheet
CUF        C Utilities Form definition                   TCU Turbo C Utilities
                                                         Resource Workshop -
CUR        Windows resource (cursor image file)          WRT - Watcom Resource
                                                         Editor
CUT        Graphics format (bitmapped graphics)          dr. Halo
CV4        Color file                                    CodeView
CVP        Cover page                                    WinFax
CVS        Graphics                                      Canvas
CVT        Backup file for CONVERTed database file       dBASE IV
CVW        Color file                                    CodeView
CW         Circuit Wizard Document                       Circuit Wizard
CWEB       C Web
CWK        Datafile                                      ClarisWorks,
                                                         Appleworks
CXX        C++ source code file                          Zortech C++
CYS        Cytoscape session file                        Cytoscape

D        D Programming Language source file          DMD
D        Directory containing configuration files    Unix
         (informal standard)
D3V      Video file                                  Nintendo DS (with ARME,
                                                     MMCF etc.)
D4D      Data                                        Draw 4D object
D4P      Data                                        Draw 4D Pro object
D64      Commodore 64 disk image
D88      Toshiba Pasopeia D88 disk image format      A series of emulators of
                                                     Japanese computers
DAA      Direct Access Archive
DAE      COLLADA file
DAF      Data file                                   Digital Anchor
DAT      AMPL data file                              AMPL
DAT      Maxum chromatograph chromatogram            Siemens Maxum
                                                     Chromatograph
DAT      LDraw (Sub)Part File, 3D Model              LDraw
DAT      Document                                    Microsoft Word Format
                                                     (old)
DAT      data                                        RSNetWorx Project
DAT      Data file in special format or ASCII
DAT      Database file                               Clarion (programming
                                                     language)
         Norton Utilities disc image data. It saves
DAT      Boot sector, part of FAT and root directory Norton Utilities
         in image.DAT on same drive.
DAT      Optical disc image (can be ISO9660, but not cdrdao, burnatonce
         restricted to)
DAT      Video CD MPEG stream
         Windows registry hive (REG.DAT Windows
DAT      3.11; USER.DAT and SYSTEM.DAT Windows 95,   Microsoft Windows
         98, and ME; NTUSER.DAT Windows NT/2000/XP/
         7)
DAT      Minecraft game data                         Minecraft
DATS     Dynamic source                              ATS
                                                     Recorded encrypted video
DAV      Proprietary DVR format                      from digital video
                                                     recorders DVR365 or
                                                     AlienDVR series^[6]
DB$      Temperature debug info                      Clarion Modula-2
DB$      Temporary file                              dBASE
                                                     Paradox - XTreeGold -
DB       Database file                               dbvista - Oracle -
                                                     XoftSpySE - Windows
                                                     thumbnail cache^[7]^[8]
DB       Configuration                               dBASE IV - dBFast
DB       Multi Edit config                           ME
DB2      Database                                    dBASE II
DB3      Database                                    dBASE III
DBA      Database file                               Turbo Prolog - DataEase
DBA      DarkBasic source code
DBC      DataBaseContainer                           Visual FoxPro
DBD      Business data                               Business Insight
DBD      Debug info                                  Clarion Modula-2
                                                     dBASE III/IV - Visual
                                                     FoxPro - dBFast - DataBoss
                                                     - DBVista - CA-Clipper -
DBF      Database file                               Visual Objects - Alaska
                                                     Xbase++ -

                                                     Advantage Database Server

DBFX     DevBox Database File                        Pudince Devbox
DBG      Debugger script                             DOS debug - Watcom
                                                     debugger
DBG      Symbolic debugging information              Microsoft C/C++
DBK      Database backup                             dBASE IV
DBL      DIBOL source file
DBL      Design Block file                           EAGLE
DBM      Datafile                                    DataEase
DBM      Menu template                               DataBoss
DBO      Compiled program                            dBASE IV
DBPro    DarkBasicPro Project
DBS      Data file used by Managing Your Money
DBS      Database in SQL Windows format
DBS      Datafile                                    PRODAS
DBS      Printer description file                    Microsoft Word, Microsoft
                                                     Works
DBT      FoxBASE+ style memo                         FoxPro 2.x
DBT      Memo file for database w/same name          dBASE IV - dBFast
DBW      Windows file                                DataBoss
DBX      DataBeam                                    GCGW
DBX      AutoCAD Database                            AutoCAD
DBX      Archive File                                Outlook Express
DC       CAD drawing file                            DesignCAD 3000 for Windows
DC6      Image file                                  Diablo II
DCA      Document Content Architecture text file     IBM DisplayWrite
DCC      Animation                                   Diablo II
DCD      CAD Drawing File                            DesignCAD 3DMax for
                                                     Windows
DCF      floppy disk image                           Disk Copy Fast
DCH      Schematic Drawing file                      DipTrace Schematic Capture
DCI      Dreamcast Save File                         Dreamcast
DCL      Delphi Control Library                      Borland Delphi
DCM      DCM music module                            AWAVE
DCP      OS/2 device code page                       OS/2
DCS      Bitmap graphics (CYMK format)               QuarkXPress
DCS      Datafile                                    ACT! Activity Files
DCT      Dictionary: used by many programs with      Clarion
         program dependent format
DCT      Spell checking dictionary                   Harvard Graphics 3.0 -
                                                     Symphony
DCT      DataBaseContainer Extension                 Visual FoxPro
DCU      Delphi unit (compiled)                      Borland Delphi
DCW      Walter Machine Programing                   Walter Profile Editor
DCX      Multi-page PCX graphics (common fax format) Intel - SpectraFAX
DCX      DataBaseContainer Index                     Visual FoxPro
DD       Macintosh file archive                      DISKDOUBLER
DDA      Data                                        GLBasic ASCII 3D object
DDB      Bitmap graphics
DDB      Digidesign Database File                    Digidesign Pro Tools
DDD      Building Diagram                            Diagramming software
DDI      Disk image                                  DiskDupe
DDP      Device Driver Profile file                  OS/2
                                                     Microsoft Flight
DDS      DirectDraw Surface file                     Simulator, other Microsoft
                                                     programs
DEB      Unix archive file (software package format) Unix
DEB      DEBUG script                                DOS Debug
DEF      Assembly header file                        Geoworks
DEF      Defaults - definitions
DEF      Linker definition file                      TLink - WLink...
DEM      Demonstration
DEM      Digital Elevation Model
DEM      Graphics file                               VistaPro
DEM      Vista DEM file                              Meta.exe VP3
DER      Security certificate                        Microsoft Windows
DES      Ascii text parameter description            AWAVE
         Windows Explorer Desktop Control (commonly
         "Desktop (create shortcut).DESKLINK", 0
DESKLINK bytes). Uses a 'special' hidden file
         extension (NeverShowExt flag inside the
         Registry), overriding the Windows Explorer
         option of showing/hiding file extensions.
desktop  Desktop Entry                               freedesktop.org
DEV      Device driver
DEV      SYSGEN handler build procedure              RT-11
DEV      Dev-C++ project file                        Dev-C++
DEX      Dalvik executable                           Android
DFD      Data Flow Diagram graphic file              Prosa
DFF      RenderWare model data (e.g. Grand Theft
         Auto III and later)
DFI      Outline font description                    Digifont
DFL      Default program settings                    Signature
DFM      Data Flow Diagram model file                Prosa
DFM      Delphi form module                          Borland Delphi
DFS      Delight Sound File
DFTI     Dynamic Formatted Text and Images (Word     FlexiWrite
         Processing)
DFV      Printing form (Word)                        Microsoft Word
DFX      Micrografx Effects DLL
DGN      Graphics file                               MicroStation
DGS      Diagnostics
DH       Dependency information for .ph              Geoworks
DHP      Dr. Halo PIC Format graphics file           Dr. Halo II - III
DHT      Datafile                                    Gauss
DI       D Programming Language interface file       DMD
DIA      Diagraph graphics file                      Computer Support
                                                     Corporation
DIB      Device Independent Bitmap                   rarely used Windows 3.0
                                                     bitmap; Win - OS/2
DIC      Dictionary (e.g. from WinWord)
DICOM    Digital Imaging and Communications in       DICOM Software (XnView)
         Medicine (DICOM) bitmap
DIF      Borland patch data file                     Borland patch
DIF      Data Interchange Format                     Visicalc
DIF      OS/2 V2.2 Display Information File          OS/2
DIF      Output from Diff command - script for Patch
         command
DIF      SRCCOM, BINCOM output file                  RT-11
DIG      Digilink                                    AWAVE
DIG      Sound Designer 1 audio file                 AWAVE
DIP      Graphics
DIP      Watcom debug info processor                 WatcomDebugger
DIP      PCB Drawing file                            DipTrace PCB Layout
DIR      Dialing directory file                      Procomm Plus
DIR      Directory file                              VAX - CPS Backup
DIR      Movie                                       MacroMind Director 4.x
DIR      Directory listing file                      RT-11
DIRED    Directory listing (ls format)               Dired
DIS      Distribution file                           VAX Mail
DIS      Thesaurus                                   CorelDraw
DIZ      Description file (Description In Zip)
         DJVU Document Format, a format similar to
DJVU     PDF but with higher compression rates at    DJVU
         the same quality.
DKB      Raytraced graphics                          DKBTrace
DL       Animation format (Italian origin)           Display - DL Viewer
DLC      JDownloader Link Container                  JDownloader
DLD                                                  Lotus 1-2-3
                                                     Produced by Exstream
DLF      Dialogue Live Format                        Dialogue and edited by
                                                     Dialogue Live Editor
DLG      Dialog resource script file                 Microsoft Windows SDK
DLG      Dialog resources                            DN
DLG      Windows SDK dialog editor data file
DLG      Windows SDK dialog editor data file
DLL      Dynamic-link library                        Windows 3.x - OS/2
DLL      Export/import filter                        CorelDRAW
DLM      Microsoft File Transfer Manager             Microsoft File Transfer
                                                     Manager
DLP      Data                                        DAQLab
DLS      Setup                                       Norton Disklock
DMF      Music format (Delusion Digital Music File)  Delusion
DMF      DeleD files
DMG      Apple Disk Image                            Mac OS X (Disk Utility),
DMO      Demo                                        Derive
DMP      Dump file (e.g. screen or memory)
DMP      DUMP utility output file                    RT-11
DMS      Amiga file archive                          DISKMASHER
DN       3D file                                     Adobe Dimension
                                                     At least 30 camera models
         Digital Negative (DNG), a publicly          from at least 10
DNG      available archival format for the raw files manufacturers, and at
         generated by digital cameras                least 200 software
                                                     products
DNT      data                                        RSNetWorx Project
DO       Java servlet file                           Web browser (Various)
         A Document, or an ASCII text file with text
DOC      formatting codes in with the text; used by  Microsoft Word and others
         many word processors
DOCM     Microsoft Word 2007 Master document         Microsoft Word 2007
DOCX     Office Open XML Text document               Microsoft Word
DOF      Delphi project options file                 Borland Delphi
DOG      Screen file                                 Laughing Dog Screen Maker
DOH      Dependency information for .poh             Geoworks
DOR      Roland Digital audio file                   Roland
DOS      External command file                       1st Reader
DOS      Network driver (e.g. pkt_dis.dos)
DOS      OS/2 V3 SVGA PMI-File                       Svga.exe
         renamed system files (AUTOEXEC.BAT,
DOS      COMMAND.COM, CONFIG.SYS,DBLSPACE.BIN,       Windows 95, 98, ME
         DRVSPACE.BIN, IO.SYS, MSDOS.SYS) of         (dual-boot feature)
         previous MS-DOS version
DOS      Text file containing DOS specific info
DOT      Line-type definition file                   CorelDRAW
DOT      Microsoft Word document template            Microsoft Word
DOTX     Office Open XML Text document template      Microsoft Word
DOX      Text file                                   MultiMate 4.0
DOZ      Description Out of Zip                      VENDINFO
DP       Calendar file                               Daily Planner
DP       Data file                                   DataPhile
DPR      Default project- and state-related          Borland C++ - Delphi - C
         information
DPF      Bareboard PCB CAD/CAM format                Ucamco
DPF      Debrief Plot File                           Debrief
DPX      Digital Moving Picture Exchange
DRP      Web3D File                                  Web3D
DRS      Data Resource File                          Age of Empires (video
                                                     game)
DRS      Display Resource                            WordPerfect for Win
DRU      Design Rules                                EAGLE
DRV      Driver
DRW      Designer vector graphics file               Designer - MicroGraphix
DS       TWAIN Data Source                           Any twain-source must
                                                     supply one xxx.ds file
DS1      Map file                                    Diablo II
DS4      Vector graphics                             Micrografx Designer 4.x
DSC      Celestia Deep Space Catalog file            Celestia
DSC      Description file
DSC      Discard file                                Oracle
DSD      Database                                    DataShaper
DSF      Data Storage Format                         Golden Helix
DSF      Delusion Digital Sound File                 Delusion
DSK      Desktop configuration                       BP - DN - BC++ - TP
DSK      Disk Drivers                                Novell NetWare
DSK      Logical disk file                           RT-11
DSM      Digital Sound Module                        DSI
DSN      Design                                      Object System Designer
DSP      Display parameters                          Signature
DSP      Dynamic Studio Professional Module          Dynamic Studio
DSP      Graphics display driver                     Dr. Halo
DSP      Norton viewer DLL                           Win
DSP      Visual Studio 6 project file                Microsoft Visual Studio
DSR      Driver Resource                             WordPerfect for Win
DSS      Screensaver file                            DCC
DSS      Digital Speech Standard (Sound)             Digital Soup
DSS      SQL Script for .Time Framework              Exaktime
DST      Tajima Embroidery Format                    Embroidermodder
DST      WAIN (Scanner spec) data source DLL         Win
DSV      Nintendo DS battery save                    DeSmuME, DraStic
DSW      Borland C++ 4.x desktop layout file         BCW.EXE
DSY      DAISY container file                        ADAKTA.EXE
DT1      Tile file                                   Diablo II
DT2      msn-emoticon                                paint
DT_      Data fork of a Macintosh file               Mac-ette
DTA      Data file                                   Turbo Pascal - PC-File -
                                                     Stata
DTB      Database Backup for .Time Framework         Exaktime
DTD      Document Type Definition
DTF      Database file                               PFS - Q&A
DTL      Django template language                    djangoproject
DTM      DigiTrekker music module                    AWAVE
DTO      data                                        Directory Toolkit output
                                                     Timeworks / greenstreet
DTP      Desk Top Publishing Document                Publisher3/ Greenstreet
                                                     Publisher 4.5
DTP      Page Magic 2.0 publication                  Page Magic 2.0 upgrades to
                                                     Greenstreet Publisher
DTP      Publication                                 Publish-It! upgrades to
                                                     Greenstreet Publisher
DTS      Torque Game Engine model format
DTS      Device tree source file                     Linux kernel project
DTSI     Device tree include file                    Linux kernel project
DVC      Data                                        Lotus 1-2-3
DVDPROJ  iDVD project file                           iDVD (Apple iLife '08)
DVI      DeVice Independent document                 TeX
DVP      DESQView run-file                           DESQView
DVP      Device parameter file                       AutoCAD
DW2      Drawing                                     DesignCAD for DOS, &
                                                     DesignCAD for Windows
DWB      Coryphaeus Software Designers Workbench     CSD
DWC      Archive                                     DWC
DWD      DiamondWare Digitized file                  AWAVE
DWF      Autodesk Design Web Format                  Design Review
                                                     AutoCAD, IntelliCAD,
DWG      Drawing                                     PowerCAD, Drafix,
                                                     DraftSight etc.
DWZ      DVD MovieFactory for TOSHIBA Project File,  Designer - MicroGraphix or
         Designer vector graphics file               TOSHIBA
DX       Text file                                   DEC WPS/DX format - DEC
                                                     WPS Plus
DXF      Dialogue Exchange Format                    Exstream Dialogue
DXF      Drawing Interchange File Format vector      AutoCAD, IntelliCAD,
         graphics                                    PowerCAD, etc.
DXN      Fax                                         Fujitsu dexNET
DXP      SpotFire data                               TIBCO Spotfire
DXP      ISO creation project file                   CD Burner XP Pro
DYLIB    Dynamic Library                             Mac OS-X
DYN      Data                                        Lotus 1-2-3

E      E language source code                   E
E##    EnCase Evidence File chunk               EnCase Forensic Analysis Suite
                                                entity
E00    ArcInfo interchange file                 GIS software
E2D    2-dimensional vector graphics file       Editor included in JFire
EAS    Extended file attributes                 OS/2
EAR    Enterprise archive                       archive
EBA    Source code                              Emergence BASIC
       versions of DOS system files (
EBD    AUTOEXEC.BAT, COMMAND.COM, CONFIG.SYS,   Windows 98, ME
       WINBOOT.SYS, etc. ) for an emergency
       boot disk
EBJ    Error-checking object file               Geoworks
EBQ    CITE standard electronic BQ exchange
       file
EC     Error checking preprosessed Goc source   Geoworks
       code
EC     Source code                              eC
ECC    Error-checking file                      dvdisaster
ECE    Escenic Contenting Engine dynamic page   Escenic
ECMS   Status document                          ECMerge
ECMT   Template document / Session              ECMerge
ED5    EDMICS                                   GCGW
EDA    Ensoniq ASR disk image                   AWAVE
EDE    Ensoniq EPS disk image                   AWAVE
EDF    European data format                     Medical timeseries storage
                                                files
EDF    Exchequer Document Format                IRIS Software
EDK    Ensoniq KT disk image                    AWAVE
EDL    EDL                                      Premiere
EDQ    Ensoniq sq1,2/ks32 disk image            AWAVE
EDS    Ensoniq SQ80 disk image                  AWAVE
EDT    Default settings                         VAX Edt editor
EDT    Ensoniq TS disk image                    AWAVE
EDT    External editors definitions             DN
EDV    Ensoniq VFX-SD disk image                AWAVE
EEB    Button bar for Equation Editor           WordPerfect for Win
EFA    Ensoniq ASR file                         AWAVE
EFA    Encrypted File Archive
EFE    Ensoniq EPS file                         AWAVE
EFE    Ensoniq EPS instrument file              AWAVE
EFK    Ensoniq KT file                          AWAVE
EFQ    Ensoniq SQ1/SQ2/KS32 file                AWAVE
EFS    Ensoniq SQ80 file                        AWAVE
EFT    Ensoniq TS file                          AWAVE
EFT    High resolution screen font              ChiWriter
EFV    Ensoniq VFX-SD file                      AWAVE
EFX    Fax                                      Everex EFax
EGA    EGA display font                         Ventura Publisher
EIS    EIS Spectrum Analyser Project            EIS Spectrum Analyser
EKA    Internal data files                      Borland's Eureka
EL     Emacs Lisp source code file              Emacs
ELB    Synergy/DE library
ELC    Byte-compiled Emacs Lisp code            Emacs
ELFO                                            ElsterFormular
ELI    Archive                                  ELI
ELT    Event list text file                     Prosa
EMAIL  Outlook Express Email Message            Windows Live Mail, Outlook
                                                Express, Microsoft Notepad
EMAKER E language source code (maker)           E
EMC    Striata Reader Encrypted Document Format
EMD    ABT Extended MoDule                      AWAVE
EMF    Microsoft Enhanced Metafile
EML    Stationery Template                      Outlook Express
EMU    Terminal emulation data                  BITCOM
EMZ    Microsoft Enhanced Metafile compressed   Microsoft Office suite
       with ZIP
ENC    Encoded file - UUENCODEd file            Lotus 1-2-3 - uuexe515.exe
ENC    Music                                    Encore
END    Arrow-head definition file               CorelDRAW
ENFF   Extended Neutral File Format
ENG    Dictionary engine                        Sprint
ENG    English documentation
ENG    Graphics file (charting)                 EnerGraphics
ENV    Envelope or Environments
ENV    Enveloper macro                          WOPR
ENV    Environment file                         WordPerfect for Win
EOSSA  Electro-Optic Space Situational
       Awareness file format
EOT    Embedded OpenType
EP     GUI wireframe/prototype project          Prikhi Pencil, Evolus Pencil
EPA    Award BIOS splash screen                 Award BIOS, XnView
EPD    Publication                              Express Publisher
EPI    Document                                 Express Publisher
EPI    Encapsulated PostScript graphic file
       Encapsulated PostScript (Graphics        CorelDraw - PhotoStyler -
EPS    format)                                  PMView - Adobe Illustrator -
                                                Ventua Publisher
       Electronic Publication - (e-Reader       Okular (Linux) - Apple iBooks -
EPUB   format)                                  Sony Reader - Adobe Digital
                                                Editions - Calibre (LMW)
EQN    Equation filE                            WordPerfect for Win
ERD    Entity Relationship Diagram graphic file Prosa
ERL    Erlang source code file
ERM    Entity Relationship Diagram model file   Prosa
ERR    Compiler/linker error report
ESCPCB Data file of "esCAD pcb", PCB Pattern    esCAD pcb provided by
       Layout Design Software                   Electro-System
ESCSCH Data file of "esCAD sch", Drawing        esCAD sch provided by
       Schematics Diagram Software              Electro-System
ESH    Extended Shell batch file
ETH    Document                                 Ethnograph 3
ETF    Encrypted Text File. Used in some
       security programs.
ETL    event trace log file                     Microsoft^[9]^[10]
ETW    Proprietary format from EnterTech for    Enter-Tech
       the MagicSing/Mic Karaoke product line.
ETX    Structure-enhanced text for some ascii
       text browsers
EUI    Ensoniq EPS family CD image              AWAVE
EVT    Events descriptions
EVT    Windows Event log file                   Microsoft Windows NT 4.0 - XP;
                                                Microsoft Event Viewer
EVTX   Windows Event log file XML structured    Microsoft Windows Vista, 7, 8;
                                                Microsoft Event Viewer
EVY    Document                                 WordPerfect Envoy
EWD    Document                                 Express Publisher for Windows
                                                Elixir programming language
EX     Elixir source code file                  running on BEAM (Erlang virtual
                                                machine)^[11]
EX3    Device driveR                            Harvard Graphics 3.0
EXB    Audio File                               E-MU Systems Emulator X Sampler
                                                File
EXC    Exclude file for Optimize (do not        QEMM
       process) (QEMM)
EXC    REXX source code file                    VM/CMS
EXE    Directly executable program              DOS, OpenVMS, Microsoft Windows
                                                , Symbian or OS/2
EXF    Exactal Exchange File                    CostX
EXF    Excute file                              OnHand PC
EXM    MSDOS executable, system-manager         HP calculator
       compliant (HP calculator)
EXP    Drawing File format                      Drawing Express
EXP    Melco Embroidery Format                  Embroidermodder
EXP    Protected mode EXE by PharLap Software   PharLap
EXP    Exports Library File                     VisualStudio
EXS    Audio File                               Apple Logic Pro EXS instrument
EXS    Elixir script file                       Interactive Elixir (IEx) shell^
                                                [12]
EXT    Extensions descriptions file
EXX    Intermediate file by MsgPut              IBM LinkWay
EZW    easyOFFER document file^[13]             easyOFFER by Reagency Systems
                                                Corp.
EZF    Fax                                      Calculus EZ-Fax

F              Archive                                   FREEZE
F              Forth language source code file           Forth development
                                                         systems
F              Fortran language source code file (in     Many Fortran compilers
               fixed form)
F01            Fax                                       perfectfax
F03            Fortran language source code file (in     Many Fortran compilers
               free form)
F2R            Farandole Linear Module                   Farandole
F3R            Farandole Blocked Linear Module           Farandole
F4             Fortran IV source code file
F4A            Flash Video F4V with only audio (see also Adobe Flash
               SWF)
F4B            Flash Video F4V audiobook (see also SWF)  Adobe Flash
F4P            Flash Video F4V with digital rights       Adobe Flash
               management (see also SWF)
               A container format for Flash Video that
F4V            differs from the older FLV file format    Adobe Flash
               (see also SWF)
F77            Fortran language source code file (in     Many Fortran compilers
               fixed form)
F90            Fortran language source code file (in     Many Fortran compilers
               free form)
F95            Fortran language source code file (in     Many Fortran compilers
               free form)
F96            Fax                                       Frecom FAX96
FA             FASTA format sequence file
FAC            see FACE
FACE           Usenix FACE graphics file
FAM            Famtasia Famicom image format             Famtasia
FAQ            Frequently Asked Questions text file
FAR            Music format (Farandole Composer Module)  Farandole
FAS            Macsyma compiled program
FASTA          FASTA format sequence file
FAX            Fax (raster graphics in CCITT format)     most Fax programs
FB             Backup files                              Fifth Generation
                                                         Systems FastBack Plus
FB2            FictionBook e-book 2.0 file (DRM-free XML e-book readers
               format)
FB2K           foobar2000 File                           foobar2000
FB2K-COMPONENT foobar2000 Component                      foobar2000
FBM            Fuzzy Bitmap
FBW            HP Backup and Recovery Manager            HP Backup
               3D model geometry, material textures,
FBX            lighting, armature, and animation         Autodesk
               sequences for inter application use/
               transport
FC             Spell checking dictionary                 Harvard Graphics 2.0
FCM            Binary file patch file (forward           jlpak10.zip
               compression)
FCS            Flow cytometry standard file
FCP            Final Cut Pro project file                Final Cut Pro
FD             Declaration file                          Microsoft Fortran
FD             Field offsets for compiler                DataFlex
FD             Front Door' resource files                FD
FDB            Font Definition Block                     Ming library
FDS            fwNES Famicom Disk System image           fwNES
FDS            Headerless Famicom Disk System image
FDW            Form                                      F3 Design and Mapping
FDX            Screenplay                                Final Draft
FE             Data                                      Surface Evolver 3D
                                                         surface
FEB            Button bar for Figure Editor              WordPerfect for Win
FEI            Fatal Error Infotable                     Geoworks
                                                         Chess applications
FEN            ForsythEdwards Notation                  -text data describes a
                                                         specific position.
FES            File produced when a fileless occurrence  3D Topicscape
               in 3D Topicscape is exported to Windows
FF             Intelligont FIAS format
FF             Outline font description                  Agfa Compugraphics
FFE            Front Fareast Famicom image format
FFF            Fax                                       defFax
FFI            Atech FastFont (AllType)
FFIVW          File Format for the Interchange of
               Virtual Worlds
FFT            Dca/FFT Final Form Text text file
               (DisplayWrite)
FFT            DCA/FFT Final Form Text text file         DisplayWrite
FH3            Vector graphics                           Aldus FreeHand 3.x
FH4            Vector graphics                           Aldus FreeHand 3.x
FI             Interface file                            Microsoft Fortran
FIF            Fractal Image Format file
FIG            Figure File                               MATLAB
FIL            Table Data                                Audit Command Language
                                                         (ACL)
FIL            File template                             Application Generator
FIL            Filelist
FIL            Files list object file                    dBASE Application
                                                         Generator
               Mirror. FIL is the name given to the
FIL            saved FAT by the mirror program included  MS-DOS -
               in some versions of DOS and in PCTools
FIL            Overlay                                   WordPerfect
FIL            File which was moved to the Virus Vault
               by AVG
FILE           A generic Windows file
FILM           Filmkey film file                         Filmkey Player
FIN            Print-formatted text file                 Perfect Writer -
                                                         Scribble - MINCE
FIO            Aldus PhotoStyler graphics filter
FIO            Image PALS viewer DLL
FIT            File Index Table                          WindowsNT
FIT            see FITS
FIT            Fityk Script                              Fityk
FITS           Flexible Image Transport System           astronomy software
FIX            Patch file
FKY            Macro file                                FoxPro
FLA            Source material for Flash applications    Adobe Flash
               (see SWF)
FLAC           Audio codec, Audio file format
FLAME          Fractal configuration file                Apophysis
FLB            Format library                            Papyrus
FLC            Animation format FLIC >320x200            AAPlay - Autodesk
                                                         AniPro
FLD            Folder                                    Charisma
FLI            Animation format FLIC 320x200             Autodesk Animator
FLI            TeX font library                          EmTeX
FLM            Film Roll                                 AutoCAD/AutoShade
FLP            Flstudio project file                     Fruity Loops
                                                         (FlStudio)
FLP            FLP Designer layout file                  FLP Designer
FLT            Data/file conversion filter (or overlay)  Alsud, Microsoft Word
FLT            Filter file                               Micrografx Picture
                                                         Publisher
FLT            MultiGen Flight
FLT            Support file - graphics filter            Asymetrix ToolBook
FLX            Animation format
FLX            Compiled binary                           DataFlex
FLV            A container format for Flash Video (see   Adobe Flash
               also SWF)
FM             Database                                  FileMaker Pro
FM1            Spreadsheet format overlay                Lotus 1-2-3 release
                                                         2.x
FM3            Device driver                             Harvard Graphics 3.0
FM3            Spreadsheet                               Lotus 1-2-3 release
                                                         3.x
FMB            File Manager Button bar                   WordPerfect for Win
FMF            Font or icon file                         IBM LinkWay
FMK            Makefile                                  Fortran PowerStation
FMO            Compiled format file                      dBASE IV
FMT            Format file                               dBASE IV - FoxPro -
                                                         Clipper 5 - dBFast
FMT            Gate3 format file
FMT            Style sheet                               Sprint
FMV            Full Motion Video file
FN3            Font file                                 Harvard Graphics 3.0
FND            Files searching properties                Win95
FNI            FileNet Native Document                   FileNet
FNK            FunkTracker music module                  AWAVE, FunkTracker
FNM            Fannie Mae Residential Loan Data (RLD)    Desktop Originator
               format for mortgage submission to DO/DU
Fnn            DOS screen text font - height nn pixels   fntcol13.zip
FNT            Font file                                 many
FNX            Inactive font                             Exact
FO1            Font file                                 Borland Turbo C
FO2            Font file                                 Borland Turbo C
FOG            Fontographer Database File                Fontographer 3.5
FOL            Folder of saved messages                  1st Reader
FON            Log of all calls                          Procomm Plus
FON            Terminate phonebook                       Terminate - Terminator
                                                         - Telix
FON            Windows bitmapped font file               Win
FONT           Font data                                 unix
FOP            Freedom of the Press graphic file
FOR            Form                                      WindowBase
FOR            Fortran language source file              many
FOT            Installed Truetype font                   Windows Font Installer
FOX            Foxbase executable (precompiled .prg)     FoxBase
FP             Final Page file                           FoxPro for DOS
FP             Tiff file                                 TIFF/IT P1
FP             Video file                                DVICO/TVIX MPEG1 video
                                                         file
FP3            Database                                  FileMaker Pro
FP4            Database                                  FileMaker Pro
FP5            Database                                  FileMaker Pro
FP7            Database                                  FileMaker Pro
FPC            Catalog                                   FoxPro
FPD            TMT Pascal compiled unit                  TMT Pascal
FPL            Playlist
FPM            Configuration file                        FoxPro for MacIntosh
FPT            Foxpro memo field tables                  FoxPro
FPU            Configuration file                        FoxPro for Unix
FPW            Floorplan drawing                         FloorPLAN plus for
                                                         Windows
FPW            Configuration file                        Visual FoxPro
FPX            FlashPix Bitmap Image File                FlashPix
FR?            Packed mail                               FTN software
FR3            Renamed dBASE III+ form file              dBASE IV
FRF            FontMonger Database file                  FontMonger
FRG            Uncompiled report file                    dBASE IV
FRL            GP-Forth library                          GP-Forth
FRM            Registration or other form
FRM            Report file                               dBASE IV - Clipper 5 -
                                                         dBFast
FRM            Visual Basic Form                         Visual Basic
FRM            MySQL Database Metadata                   MySQL
FRO            Compiled report file                      dBASE IV
FRP            Form                                      PerForm PRO Plus -
                                                         FormFlow
FRS            Screen Font Resource                      WordPerfect for Win
FRT            Additional (FPT) report description file  FoxPro
FRT            GP-Forth source file                      GP-Forth
FRX            Main (DBF) report description file        Visual FoxPro
FRX            Visual Basic binary program file          Visual Basic
FSA            Applied Biosystems Genetic Analysis data  GeneScan
               file
FSIM           Simulation File Format                    Loudsoft
FSL            Form                                      Paradox for Windows
FSM            Farandole Composer WaveSample             Farandole
FSPROJ         Habanero Firestarter project              Habanero Firestarter
FST            Linkable program                          dBFast
FST            Temporal database file                    GTKWave data file
FSTICK         Temporal database file                    Flash Joystick
FSX            Data                                      Lotus 1-2-3
FTB            Compressed Ftb file                       Family Tree Builder
FTH            foobar2000 Theme File                     foobar2000
FTM            Font file                                 Micrografx
FTS            Full text search index of old Windows     Windows 3.0 - XP
               Help file
FTXT           text                                      Cloanto text document
FTP            Configuration                             FTP Software PC/TCP
FUK            Map File                                  Postal 2
FW             Database                                  FrameWork
FW2            Database                                  Framework II
FW3            Database                                  Framework III
FWEB           Fortran WEB
FX             On-line guide                             FastLynx
FXD            Phonebook                                 FAXit
FXP            Foxpro executable (precompiled .prg)      Visual FoxPro
FXS            FAX Transmit Format graphics file         WinFax
FYF            FileLoc                                   FyTek, Inc.

G                Data chart                               APPLAUSE
G16              GoldED for DOS compiled config           GOLDED.EXE
G3               Group 3 Fax                              Netpbm, ImageMagick,
                                                          XnView
G3D              Glest model file                         G3D viewer
G3P              data                                     Grand Prix 3 car
                                                          physics
G8               Raw graphics file (one byte per pixel)   PicLab - Cubicomb
                 plane three                              Picturemaker
GAF              Globa Game Engine audio format           Globa Game Engine
GAM              Fax                                      GammaFax
GAME             Chess Game                               macOS Chess
GAMEPROJ         Gamesalad game project format            GameSalad
gaupol-extension                                          Gaupol
GB               Game Boy ROM                             Nintendo
GB               GenBank flat file
GB1              Game Maker backup file (can also be GB2,
                 GB3, etc.)
GBA              Game Boy Advance ROM                     Nintendo
GBC              Game Boy Color ROM                       Nintendo
GBK              GenBank flat file
GBL              Genesis Bitmap Layout                    Genesis Bitmap
GBL              Global definitions                       VAXTPU editor
GBL              Global module in Basic programs          Basic
GBP              Genesis Bitmap Pattern                   Genesis Bitmap
GBS              GBS meta data                            Generic Build Support
                                                          (GBS)
GBR              Gerber format                            PCB CAD/CAM
GBR              GIMP brush
                                                          Star Wars:
GC               Savegame                                 Battlefront II
                                                          Galactic Conquest
                                                          save file
GC1              Lisp source code                         Golden Common Lisp
                                                          1.1
GC3              Lisp source code                         Golden Common Lisp
                                                          1.3
GCA              IBM GOCA                                 GCGW
GCD              Graphics                                 ROBLOX
GCD              General content descriptor               Wireless devices
GCD              Generic Cadd drawing                     Generic Cadd, Visual
                                                          Cadd
GCF              Game cache file                          Steam content
                                                          delivery system
GCH              GNU preprocessed C++ header file         GNU C++ compiler
GCI              Nintendo GameCube save file              Nintendo GameCube
GCW              Microsoft Mathematics Worksheet          Microsoft Mathematics
GCX              Graph file                               Mac OS X Grapher
GD3              Game Doctor Super NES ROM image
                 General Data Format for Biomedical       Biomedical signal
GDF              Signals                                  processing, Brain
                                                          Computer Interfaces
GDF              Dictionary file                          GEOS
GDF              Geographical Data Format                 Various mapping
                                                          software
GDF              IBM Graphics Data Format                 Legacy IBM systems
GDL              Data                                     ArchiCAD model
GDS              McDonnell-Douglas Things
GDT              Gerätedatentransfer, an xDT application  Healthcare providers
                                                          in Germany
GE               GEcho config file                        GEcho
GED              GEDCOM                                   Genealogy data
                                                          exchange
GED              Native format for all A&L products since Arts & Letters
                 1983
GED              GoldED for DOS compiled config file      GOLDED.EXE
GED              Graphics editor file                     EnerGraphics
GED              Game Editor Data / project file          Game Editor
GEM              Vector graphics file                     GEM - Ventura
                                                          Publisher
GEN              Compiled template                        dBASE Application
                                                          Generator
GEN              Generated text                           Ventura Publisher
GENBANK          GenBank flat file
GEO              Geode                                    Geoworks
GEO              GEOS specific file (application)         GEOS
GEO              GoldED for OS/2 compiled config file     GED2.EXE
GEX              GEcho config file                        GEcho
GFB              Compressed GIF image created by GIFBLAST gifblast.exe
GFF              General feature format
GFO              SGI Radiosity
GFT              Font                                     NeoPaint
GFT              GEM-translator font file
GFX              Instant Artist graphics Files            Instant Artist
GFX              PCBoard @X-coded colorful text           GFX2COM - GFX2EXE
GHO              Norton Ghost File (first file)           Symantec
GHS              Norton Ghost File (split file)           Symantec
GHW              GHDL Wave file                           GHDL/GTKWave data
                                                          file
GIB              Chart                                    Graph-in-the-Box
GIB              GIMP animated brush
GID              Global index of old Windows Help file    Windows 3.0 - XP
GIF              Compuserves' Graphics Interchange Format QPeg - Display -
                 (bitmapped graphics)                     CompuShow
GIW              Presentation                             Graph-in-the-Box for
                                                          Windows
GKH              Ensoniq Disk Image (VFX, SD, EPS, ASR,   Ensoniq
                 TS)
GKS              Graphics Kernel System
GL               Animation format                         grasprt.exe, PV
                                                          GRASP GRAphical
GL               Animation                                System for
                                                          Presentation
GLB              Global module in Basic programs
GLM              Datafile, KernelCAD model                Glim, KernelCAD
GLO              Global module in Basic programs
GLS              Datafile                                 Across
GLY              Winword Glossary                         Microsoft Word
GM6              GameMaker Editable file as of version    Game Maker
                 6.x
GM81             GameMaker Editable file as of version    Game Maker
                 8.1.x
GMD              GameMaker Editable file up to version    Game Maker
                 5.x
GMF              CGM graphics file                        APPLAUSE
GMK              GameMaker Editable file as of version    Game Maker
                 7.x or 8.x
GML              GameMaker GML script file                Game Maker
GML              Geography Markup Language File           Geography Markup
                                                          Language
GMOD             Data                                     Golgotha 3D model
GMP              Geomorph tile map                        SPX
GMS              Ghost Mouse Script
GMS              Gesture and Motion File Formats
GMT              Gene Matrix Transposed
GMT              data                                     RFactor car physics
GMX              GameMaker:Studio Editable File as of 1.x Game Maker
GO               Go source code file                      Golang
GOC              Goc source code file                     Geoworks
GOE              GOES graphic file
GOH              Goc header file                          Geoworks
GP               Geode parameter file                     Geoworks Glue
GP4              data                                     Grand Prix 4 car
                                                          physics
GP5              Guitar Pro 5 song                        Guitar Pro 5
GPH              Graph                                    Lotus 1-2-3/G
GPK              Omnigo program package
GPL              GIMP palette file (text)                 GIMP, Inkscape
GPX              GPS eXchange Format
GR2              Screen driver                            Windows 3.x
GRA              Datafile                                 SigmaPlot
GrADS            Metafile
GRAFFLE          OmniGraffle graph file
GRASP            Graphical System for Presentation
GRB              T-FLEX CAD file                          Top Systems
GRB              MS-DOS Shell Monitor file                MS-DOS 5
GRD              Drivers for GRX (graphics library)       GRX (c) Free Soft.
                                                          Found.
                 Image format used in the core of some
GRDNT            very obscure customized operating
                 systems to represent gradients; see also
                 SCTOR
                                                          Grenoble Thermal
GRE              data                                     ellipsoids Plot
                                                          Program
GREENFOOT        Greenfoot Project                        Greenfoot
GRF              Graph file                               Graph Plus, DPlot,
                                                          and Charisma
GRFT             Graph definition text file               SELDM Postprocessor
GRIB             Gridded Binary
GRN              Drivers for GRX (graphics library)       GRX (c) Free Soft.
                                                          Found.
GRP              Group file                               Windows 3.x - Papyrus
GRP              Pictures group                           PixBase
GRY              Graphics format (RAW GREYz)
                 Script written in Google Apps Script,
GS               used for automating tasks across online  Google Apps Script
                 Google products
GS1              Presentation                             GraphShow
GS3              data                                     GameStarter
GSA              data                                     Microsoft Office
                                                          Groove Space Archive
GSD              Vector graphics                          Professional Draw
GSM              Raw GSM 6.10 audio stream                AWAVE
GSP              Geometer's Sketchpad
GSW              Worksheet                                GraphShow
GT7              RS7 Guided tour                          Redshift 7
GTA              data                                     Microsoft Office
                                                          Groove Tool Archive
GTF              Gene transfer format
GUP                                                       PopMail
GV               GrandView outline file
GVO              Data                                     GFXFX Vector Object
GWI              Groupwise File                           Local saved Email
GXL              Graphics library                         Genus
GXK              Secure Data encryption Format            Galaxkey
GZ               Archive                                  GNU zip - WinZipNT
GZR              data                                     GunZ action replay

H!    On-line help file                            Flambeaux Help! Display
                                                   Engine
H!    Pertext database                             HELP.EXE
H--   C—language header                            Sphinx C--
H     Header file (usually C language)             Watcom C/C++
H++   Header file                                  C++
HA    Archive                                      HA
HAL   Data file                                    Hyper Access Lite OS/2
HAM   Disk Drivers NPA                             Novell NetWare
HAM   Hold And Modify                              Deluxe Paint image file
HAP   Archive                                      HAP3
HAR   HTTP Archive format (JSON-format web-browser W3C draft standard
      log)
HBC   Compressed Archive File (Shrink Algorithm)   Hyperbac
HBC   Compressed Archive File (Shrink Fast         Hyperbac
      Algorithm)
HBE   Compressed, Encrypted Archive File (Shrink & Hyperbac
      AES256-bit Encryption)
HBK   MathCAD handbook                             MathCAD
HC    Header file
HCG   Document                                     HCLab
HCGS  Document                                     HCLab
HDD   data                                         disk image
HDD   HotDisc Designer label
HDF   Amiga Hard Disk Image
HDF   Help file                                    Help Development Kit
HDF   Hierarchical Data File graphics file         SDSC Image Tools
HDL   Alternate download file listing              Procomm Plus
HDMP  heap dumpfile
HDR   Datafile                                     Egret
HDR   Message header text                          Procomm Plus - 1st Reader
HDR   PC-File+ Database header
HDR   SPOT image file
HDS   Hierarchical Data System
HDW   Vector graphics                              Harvard Draw
HDX   Help index                                   AutoCAD - Zortech C++
HDZ   Amiga Zip compressed Hard Disk Image
HEP   Novell Help Librarian Data File              Novell NetWare
HEX   Hex dump
HFI   HP Font Info file                            GEM
HGL   Highlight groups definitions                 DN
HGL   HP Graphics Language graphics file
HH    C++ header file
HHH   Precompiled header file                      Power C
HHP   Help information for remote users            Procomm Plus
HHP   Microsoft HTML Help project                  Microsoft HTML Help Workshop
                                                   and Compiler
HI    Game high scores table
HIN   Molecule                                     HyperChem
HIS   History of executing/viewing/editing         DN
HIS   Yard Information File                        FYM
HKM   Stores sound in a bitmapped graphics file
HLB   Help library                                 VAX
HLP   old Windows Help file                        Windows 3.0 - XP, Help
                                                   Explorer Viewer
HLX   Multi Edit help file                         MultiEdit 5.0
HLZ   Multi Edit packed help file                  MultiEdit
HMI   Music format (MIDI)
HMM   Alternate Mail Read option menu              Procomm Plus
HMP   Music format (MIDI)
HMP   Hump Setup File - Obsolete as of version 2.4 FYM
      (See SET and SWT files)
HNC   CNC program files Heidenhain (?) dialog
HOF   Hall Of Fame (game scores)
HOM   CAD Software Data File                       PLXHOME
HP    Printout file for HP printers/plotters (HP/
      GL)
HP8   ASCII text HP Roman8 character set           NewWave Write
HP9   ASCII text HP Roman9 character set
HPF   HP LaserJet fonts                            PageMaker
HPG   see HPGL
HPGL  Plotter file vector graphics                 AutoCad - Harvard Graphics
      (Hewlett-Packard Graphics Language)
HPI   Font information file                        GEM
HPJ   Help project                                 Microsoft Help Compiler for
                                                   Windows - HC.EXE
HPK   Archive                                      HPACK
HPM   Alternate Main menu for privileged users     Procomm Plus
HPM   EMM text                                     HP NewWave
HPM   High Performance Map                         Quaestor 1.x
HPP   C++ header file                              Zortech C++ - Watcom C/C++
HPPCL Hewlett-Packard Printer Control Language
HQX   Archive (ASCII Mac)                          BINHEX
HRF   Graphics file (Hitachi Raster Format)
HRM   Alternate Main menu for limited/normal users Procomm Plus
HRZ   Graphics format                              SSTV
HS2   Monochrome image                             Postering
HSC   2-op FM music                                HSC tracker - hscplay.exe
HSH   Disk image hash file                         DriveSnapshot
HSI   Handmade Software Inc. graphics file almost  Image Alchemy
      JPEG
HST   History file                                 Procomm Plus
HTA   HTML Application                             Microsoft Windows
HTM   see HTML
HTML  Hypertext Markup Language (WWW)              Netscape - Mosaic - many
HTX   Hypertext file
HUS   Husqvarna Viking Embroidery Format           Embroidermodder
HVE   Hive file^[2]                                Microsoft
HWA   Hollywood applet                             Hollywood
HWD   Presentation                                 Hollywood Designer
HWP   Hangul Word Processor Document               Hangul (word processor)
HWS   Hollywood script                             Hollywood
HXM   Alternate Protocol Selection menu for all    Procomm Plus
      users
HXS   Microsoft Help 2 compiled help file          Microsoft Windows, Help
                                                   Explorer Viewer
HXX   C++ header file
HY1   Hyphenation algorithms                       Ventura Publisher
HY2   Hyphenation algorithms                       Ventura Publisher
HYC   Data                                         WordPerfect
HYD   Hyphenation dictionary                       WordPerfect for Win
HYP   Archive                                      HYPER

I         Preprocessor output file     Borland C Preprocessor
I         SWIG interface file          SWIG
IAK       Internet Access Kit          OS/2
IAM       Assembly file                Autodesk Inventor
IAX       Bitmap graphics (IBM Image
          Access eXecutive)
IAX       data                         InstallAnywhere.NET project
IBG       PDS graphic file
IBM       Archive (Internal IBM only)  ARCHDOS
IBRO      Robot save file              Incredibots 2
ICA       Bitmap graphics (Image
          Object Content Architecture)
ICB       Targa ICB bitmap graphics    many raster graphics editors
ICC       ICC profile                  Color Configuration for color input or
                                       output devices
ICE       LHA Archive                  Cracked LHA (old LHA), Total Commander
ICFE      IceFormula Equation          Penguin George
          Workspace
ICFM      IceFormula Math Workspace    Penguin George
ICL       Icon Library
ICM       ICC configuration
ICN       ICON source code file
ICO       Icon file                    ICONEDIT.EXE; Microsoft Windows
ID        Disk identification file
IDB       IDA database                 IDA
IDB       VC++ Minimum Rebuild         Visual C++
          Dependency File
IDC       IDA C language source        IDA
IDE       Borland C++ 4.x IDE project  BCW.EXE
IDF       MIDI instrument description
          or Intermediate Data Format
IDS       IDA imported names format    IDA
IDW       Vector graphics              IntelliDraw
IDW       Drawing file                 Autodesk Inventor
IDX       Index                        many - FoxPro; also unrelated Quicken
                                       file format
IFD       Form                         JetForm Design
IFF       Interchange Format File      EA Software - Convert (C) Villena -
          (IFF)                        Amiga
IFF       Sun TAAC Image File Format   SDSC Image Tool
IFP       Script                       KnowledgeMan
IFS       Fractal image compressed     Yuvpak
          file
IFS       Iterated fractal system file IFS Creation Kit, Apophysis
IFS       Installable file system      OS/2
          Flight tracks downloaded
          from GPS devices in the
IGC       International Gliding
          Commission's prescribed
          format
IGES      Initial Graphics Exchange
          Specification
IGF       Inset Systems                GCGW
IGF       LasershowGen Frames          LasershowGen
IGP       LasershowGen Project         LasershowGen
IHP       Watcom help file             whelp.exe
IHS       Inbound History              Bink/+
IIW       Power Point Image Importer
          Wizard
IL        hDC Designer Icon Lin dll
          format
ILB       Data                         Scream Tracker
ILG       data                         LaTeX Index Generation log
ILK       Outline of program's format  Microsoft ILink incremental linker
IM        Auran Jet indexed mesh file  Trainz
IM8       Sun Raster graphics file
IMA       Mirage vector graphics       EGO - Chart - Autumn
IMA       Disk image                   WinImage
IMG       ADEX graphic file
IMG       Disk Image                   NC 5.0
IMG       GEM bitmapped graphics file  Ventura
IMG       Image for Windows/Image for  TeraByte, Inc. dba TeraByte Unlimited
          DOS Disk image
IMG       Vivid IMG file
IMI       image                        Magellan Meridian map
IMI       image                        Magellan eXplorist map
IMMODULES Module                       GTK+
IMP       Spreadsheet                  Lotus Improv
IMQ       Image presentation           ImageQ
IMZ       Disk image                   WinImage
IN        Design II for Windows INput
          file
IN        autoconf INput file
IN$       Installation file            HP NewWave
IN3       Input device driver          Harvard Graphics 3.0
INB       Test script                  Vermont HighTest
INC       Include file                 several programming languages
IND       Data Index                   dBASE IV
INDD      InDesign Document            Adobe InDesign
                                       Sidecar file used by applications that
INF       Information text file        need to store file metadata on
          (ASCII)                      filesystems that do not support the
                                       metadata natively
INF       Install script
INF       OS/2 hypertext help system   VIEW.EXE
          file
INF       Type 1 LaserJet font         soft font installers
          information file
INFO      GNU info reader (output from info (Unix)
          Texinfo)
INFO      Icon Data (Amiga)
INGR      Intergraph Raster File
          Format
INI       Initialization file
INK       Pantone reference fills file CorelDRAW
INO       Arduino file                 Arduino
INS       Data                         WordPerfect
INS       Ensoniq Instrument File      Ensoniq
INS       Installation script          1st Reader
INS       Instrument music file
          (Adlib)
INT       Borland Interface Units
INT       Program saved in Internal    Signature
          (semi-compiled) format
INT       Source of Borland interface
          module
INX       Index                        Foxbase
IO        Archive                      CPIO
IOB       3d graphics database in TDDD Imagine
          format
IOC       Organizational chart         Instant ORGcharting!
          4DOS DESCRIPT.ION file (file 4DOS, NDOS, 4OS2, 4NT, TC, TCC, VC, DN,
          descriptions like long       ODN, NDN, Windows Commander, Total
ION       filenames, comments, or      Commander, Double Commander, XnView,
          extended attributes)         ACDSee, Newsbin Pro, V, as well as some
                                       CUI LIB-based applications
IP        Immortal Player file         Immortal Player
IPA       Apple iOS Application        iPhone, iPod touch, iPad
          Intellitec Program
IPC       Configuration - used to      Intellitec
          configure vehicle
          electronics
IPF       Interchangeable Preservation SoftPres
          Format
IPG       iPod game file               iTunes and iPod
IPH       Hi-Res Image                 InterPaint
IPL       Pantone Spot reference       CorelDRAW
          palette file
IPN       Presentation File            Autodesk Inventor
IPN       Intecplan project            Intecplan Business Plan Software
          IPS Patching Format
IPS       (International Patching      Rom hacking community
          System)^[citation needed]
IPSW      iOS firmware file            iPhone, iPod touch, iPad, Apple TV
IPT       Part file                    Autodesk Inventor
IPT       MultiColor Image             InterPaint
IPT       XnView IPTC template         XnView, XnViewMP
IPTC      XnView XML-based IPTC        XnViewMP
          template
IPYNB     IPython Notebook             Jupyter Notebook
IRRMESH   static irrMesh files
IRS       Resource (WordPerfect)       WordPerfect
          standard.irs
IRT       Data                         IRIT 3D model
IRTR      Graphicon-2000 Interactive
          Real-Time PHIGS
ISD       Spelling Checker dictionary  RapidFile
ISH       Archive                      ISH
ISMA      Output Video file            Islam Abusa'a Software
ISN       InstallShield Installer      InstallShield
          Source File
ISO       ISO-9660 table               see: List of ISO image software
IST       Digitrakker Instrument File  AWAVE
IT        Impulse Tracker music file   Impulse Tracker
IT        Settings                     intalk
          Technical indicator, trading
ITF       system or market scan source ProRealTime
          code file
ITF       Interface file               JPI TopSpeed Pascal
ITL       iTunes music library
ITN       Itinerary file               TomTom PNDs
ITR       i-Tree project files         i-Tree Software Suite
ITT       IconTweaker Theme
IV        SGI Inventor
IV-VRML   Inventor VRML Format
IVE       OpenSceneGraph 3D model
IVI       Image file                   ImmerVision
IVL       Lensflare file               ImmerVision
IVP       Panorama file                ImmerVision
IVU       User Interface file          ImmerVision
IW        Presentation flowchart       IconAuthor - HSC InterActive
IWA       Text file                    IBM Writing Assistant
IWB       Information WorkBench        Prodeo
IWD       Call of Duty Map - Game Data Activision, Inc.
          Archive
IWP       Text file                    Wang
IX        data                         dtSearch index
IZT       Izl binary token file        IZL

J2C    JPEG 2000 image
JA     Mozilla archive omni.ja                       Mozilla Firefox 4,
                                                     Thunderbird
JAD    Java Application Descriptor                   Mobile JAR, Java Games and
                                                     Applications
JAM    Jam messagebase                               FTN software
JAM    Jam music score                               Jam
JAR    Java archive                                  JAR, Java Games and
                                                     Applications
JAS    see JASC
JASC   Graphics format (JASC)
JAV    see JAVA
JAVA   Java source code file
JBD    Datafile                                      SigmaScan
JBIG   Joint Bilevel Image Group
JBX    Project file                                  Project Scheduler 4
JCN    JobClock.Net Synch File
JEF    Janome Embroidery Format                      Embroidermodder
JET    Fax                                           Hybrid JetFax
JFF    see JFIF
JFIF   JPEG File Interchange Format
JIF    see JFIF
JMS    Music format (JMusic file)                    UltraForce
JNLP   Java Network Launching Protocol               Java Web Start
JNR    Jinx! file recording                          Jinx! LED Matrix control
JNX    Saved data                                    Jinx! LED Matrix control
JNX    Garmin raster map file                        BirdsEye service
                                                     (subscription only)
JOB    Gravostyle engraving pattern file             Gravostyle/Gravograph
JOB    QUEUE output file                             RT-11
JOR    Journal file SQL
JOU    Journal backup                                VAX Edt editor
JP2    JPEG 2000 image
JPC    Graphics                                      Japan PIC
JPEG   Joint Photographic Experts Group graphics     QPeg - FullView - Display
       file format
JPG    Joint Photographic Group
       backup of startup files (AUTOEXEC.BAT,
JPS    CONFIG.SYS, 4DOS.INI) by installation of 4DOS 4DOS
       (JP Software)
JRE    Java Runtime Environment                      Java
JRN    JMP journal                                   JMP
JS     JavaScript file                               script in HTML pages
JSON   JSON (JavaScript Object Notation)             Ajax
JSONLD JSON-LD, a JSON-based Serialization for
       Linked Data
                                                     Dynamic pages running Web
JSP    JavaServer Pages                              servers using Java
                                                     technology
JTF    Fax                                           Hayes JT Fax
JTF    Graphics (TIFF file with JPEG compression)
JVX    Data                                          JavaView object
JW     Text document                                 JustWrite
JWL    Library                                       JustWrite
JZZ    Spreadsheet                                   Jazz

K2A    Data                                    Prince of Persia 3D object
K3D    Description of macro language 3DS       3DS
K7Z    Keysight 7-Zip File                     Keysight PathWave FPGA
KAP    Map Info Sea Chart
KAR    Music format (Karaoke)                  ITune 1000.Corp
KAR    Precompiled .prg for KARAT              Rus. FOX+ 2.0
KB     Keyboard script                         Borland C++ 4.5
KB     Program source                          Knowledge Pro
KB     K-Brief in XML format                   TCC's Set-Based Thinking™ Tools
KBA    K-Brief Attachment                      TCC's Set-Based Thinking™ Tools
KBASIC Source                                  KBasic
KBD    Keyboard mapping                        LocoScript - Signature - Procomm
                                               Plus
KBM    Keyboard mapping                        Reflection 4.0
KBS    K-Brief in Encrypted format             TCC's Set-Based Thinking™ Tools
KBZ    K-Brief in Compressed format            TCC's Set-Based Thinking™ Tools
KCL    Lisp source code                        Kyoto Common Lisp
KD     Koara Document                          Koara
KDB    KeePass 1.x database file               KeePass
KDBX   KeePass 2.x database file               KeePass
KDC    Kodak Digital Camera (graphics)         PhotoEnhancer by PictureWorks
KEP    (unknown)                               (unknown)
KEX    Kedit Macro File                        Kedit
KEXT   macOS Kernel Extension^[3]              macOS
KEY    Datafile                                Forecast Pro
KEY    Keynote presentation file               Keynote
KEY    Keyboard macros
KEY    OS/2 archive .key-file (i.e. OS2.KEY)   OS/2
KEY    Security file e.g. Shareware
       Registration info
KEY    Keynote                                 iOS devices, Macintosh
KFN    complex music format|^[4]               Karafun Karaoke(R)
KFX    Kofax Group                             GCGW
KFDK   Keysight PathWave FPGA Design File      Keysight PathWave FPGA
KIT    Power Chords drum kit file              Power Chord
KMC    KatzReview's MegaCrammer
KML    Kedit Macro Library                     Kedit
       Keyhole Markup Language                 Google Earth
KMY    data                                    KMyMoney
KMZ    Keyhole Markup Language (Zip            Google Earth
       compressed)
Knn    Database key file                       Clarion
KNO    Personal Knowbase data file             Personal Knowbase
KO     linux kernel object file                linux kernel
KODU   Kodu game save file                     Kodu Game Lab
KPL    source code                             Phrogram
KPP    Toolpad                                 SmartPad
KPS    IBM KIPS bitmap graphics
KR1    Kurzweil 2000 sample file               AWAVE
KR2    Kurzweil 2000 sample file               AWAVE
KRZ    Kurzweil K2000 File                     Kurzweil
KS     Source code                             KonsolScript Document
KS3    Data                                    3D Forgastest Editor object
KSM    Pfaff Embroidery Format                 Embroidermodder
KT     Kotlin source code                      Kotlin Programming Language
KTU    Know The Unknown Online Service Packs   Unknownsoft
KWB    Knowledge WorkBench                     Prodeo
KYB    Keyboard mapping                        FTP Software PC/TCP

L        LEX source code file
L        Linker directive file                      WATCOM wlink
L        LISP source code file
LA0      Datafile                                   SCUMM index file
LAB      Datafile                                   NCSS - SOLO
LAB      Mailing labels                             Q+E for Microsoft Excel
LAN      Erdas image file
LAN      LAN Drivers                                Novell NetWare
LANG     Language file                              Minecraft, Skype
LAS      Lasso File                                 Lasso Programming Language
                                                    File
LASSO    Lasso File                                 Lasso Programming Language
                                                    File
LAY      Word chart layout                          APPLAUSE
LBG      Label generator data                       dBASE IV
LBL      Label                                      dBASE IV - Clipper 5 -
                                                    dBFast
LBM      Graphics format (Amiga)                    Pic-view - Deluxe Paint
LBM      Linear bitmap graphics                     XLib
LBO      Compiled label                             dBASE IV
LBR      .LBR Archive                               for CP/M and MS-DOS using
                                                    the LU program
LBR      Display driver                             Lotus 1-2-3
LBR      EAGLE library file                         EAGLE (program)EAGLE
LBT      Additional (FPT) label description file    FoxPro
LBX      Main (DBF) label description file          FoxPro
LCF      Linker Control File                        Norton Guides compiler
LCH      Chart                                      IBM Works for OS/2
LCK      Lockfile                                   Paradox
LCL      Data (FTP Software PC/TCP)
LCL      Data                                       FTP Software PC/TCP
LCN      Lection                                    WordPerfect
LCS      Datafile                                   ACT! History Files
LCW      Spreadsheet                                Lucid 3-D
LD       Long Distance codes file                   Telix
LDA      Absolute binary file (load image)          PDP-11, RT-11
LD1      Overlay file                               dBASE
LDB      Data filer database                        IBM Works for OS/2
LDB      Overlay file                               Microsoft Access
LDF      Data filer form                            IBM Works for OS/2
LDF      Library definition file                    Geoworks Glue
LDT      Labordatenträger, an xDT application       Healthcare providers in
                                                    Germany
LE       DOS/4GW executable image                   DOS/4GW PM 32X DOS Extender
LES      Lesson (check *.cbt)
LEV      Level file                                 NetHack 3.x
LEX      Dictionary                                 Microsoft Word - Lexicon
LFL      LucasArts resource file
LFD      LucasArts resource file                    LucasArts games
LFT      Laser printer font                         ChiWriter
LG       Logo procedure definitions                 LSRHS Logo
LGO      Logo for header and footer                 SuperFax
LGO      Startup logo code                          Windows 3.x
LGP      LG Plate file                              Lase Graphic Number plate
                                                    software
LGS      LG Sign file                               Laser Graphic Signs
                                                    Software
LHA      LHA Archive                                LHA/LHARC, Total Commander
LHW      Amiga archive                              LHWARP
LIB      Library file                               several programming
                                                    languages
LIC      License file used by some programs to put
         their license on disk
LICENSE  License file used by some programs to put
         their license on disk
LIF      Archive
LIF      CA Clipper packed file                     CA Clipper installer
LIF      Logical Interchange Format data file       Hewlett-Packard
LIM      Archive                                    LIMIT
LIN      Line types                                 AutoCAD
LIS      Listing                                    VAX
LISP     LISP source code file
LIT      Microsoft E-book file                      Microsoft Reader
LIT      Web3D File                                 Web3D
LIX      Log file (history)                         Audit Command Language
                                                    (ACL)
LJ       Text file for HP LJ II printer
LL       LLVM Assembly Language                     llvm
LL3      LapLink III related file (document)        LapLink III
LM       Auran Jet LOD mesh table (text file to     Trainz
         control LODs)
LMP      Doom lump (data file, commonly "demo"      Doom - Doom2
         recordings)
LNG      Language definition file
LNK      Linker response file                       .RTLink
LNK      Linker script
LNK      Windows 95 shortcut                        Windows 95
LNK      Windows XP shortcut                        Windows XP
LOADERS  Loaders                                    GTK+
LOCK     Lockfile                                   Various systems
LOD      Load file
LOG      Log file                                   Numerous systems
LOM      3D Model                                   Lock On: Modern Air Combat
LOVE     LÖVE Game File                             LÖVE
LPC      Printer driver                             TEKO
LRC      Lyrics data
LRF      Linker response file                       Microsoft C/C++
LRF      Unencrypted BroadBand eBook file           Sony Librie eBook reader
LRMODULE Adobe Photoshop Lightroom Module           Adobe Photoshop Lightroom
LRP      Report                                     IBM Works for OS/2
LRPLUGIN Adobe Photoshop Lightroom Plug-in          Adobe Photoshop Lightroom
LRS      Language Resource File                     WordPerfect for Win
LRWEB    Adobe Photoshop Lightroom Web Gallery      Adobe Photoshop Lightroom
LRX      Encrypted BroadBand eBook file             Sony Librie eBook reader
LS       LiveScript source code file
LSA      Lightscape Technologies ASCII
LSA      Lingvo system audio                        ABBYY Lingvo
LSB      Lightscape Technologies Binary
LSC      Leostream Connect file                     Leostream Corporation
LSD      Lingvo system dictionary                   ABBYY Lingvo
LSP      LISP source code file                      Xlisp, AutoLISP
LSS      Spreadsheet                                Legato - IBM Works for OS/2
LSS      SYSLINUX Splash Screen Graphic             SYSLINUX, XnView
LST      Aus. BOM Hourly weather Data
LST      Filelist                                   FRQView
LST      Keyboard macro                             1st Reader
LST      List file (archive index - compiler
         listfile)
LST      Listing (e.g. source code)
LST      Map list                                   Holux - Alan
LST      Spool file                                 Oracle
LST      SLP output file                            RT-11
LTA      Data                                       LithTech ASCII 3D object
LTM      Form (Lotus Forms)                         Lotus
LUA      Lua script file                            Microsoft Visual C++,
                                                    Notepad++
LUD      Lingvo user dictionary                     ABBYY Lingvo
LUW      label data file                            Labels Unlimited for
                                                    Windows
LUX      2D and 3D graphics data file               Foliomap and Spectramap
LUZ      3D graphics data file                      Spectramap CUDA
LWD      Text document                              LotusWorks
LWO      Lightwave Object Format
LWP      Word processor                             IBM Works for OS/2, Lotus
                                                    Wordpro
LXF      Lego Exchange Format                       Lego Digital Designer data
                                                    file
LXO      Luxology scene                             modo3D software
LXT      Temporal database file                     GTKWave data file
LY       LilyPond Notation File                     LilyPond
LYR      Lyrics (ASCII)
LYT      Document Layout file                       Adminsoft Accounts
LZ       Archive                                    Lzip
LZD      Difference file for binaries               LDiff 1.20
LZH      LHA Archive                                LHA/LHARC, Total Commander
LZS      LHA Archive                                LARC, Total Commander
LZW      Archive                                    LHWARP
LZX      Amiga Archive                              LZX

M          Mathematica Package File                 Mathematica
M          MATLAB M-File                            MATLAB
M          Mercury Source File                      Mercury
M          Source code                              Objective-C
                                                    Blizzard Entertainment
M2         WoW Model Object file                    games (World of Warcraft/
                                                    Warcraft series)
M2TS       MPEG 2 Transport Stream                  Various media playback
                                                    devices / software
M3U        M3U playlist file                        Winamp, XMMS
M3U8       Unicode version of M3U playlist file     Winamp, XMMS
           (UTF-8)
M4         m4 macro file
M4A        Advanced Audio Coding
M4V        Advanced Video Coding (See MP4)
M4P        Advanced Video Coding (Protected)        iTunes
M4r        iPhone ringtone                          iTunes and iOS devices
M7P        Multilizer 2007 and 2009 localization    Multilizer
           project file
M8M        8MAM8 Model File
MAFF       Mozilla Archive Format                   Mozilla Firefox (with
                                                    add-on)
MAI        Mail                                     VAX
MAK        Makefile
MAK        Project file                             VB  VC ++
MAN        User guide (manual)
MANAGER    Accounting data file                     Manager  free accounting
                                                    software
MANIFEST   Manifest file
MAP        Color palette file
MAP        Format data                              Micrografx Picture
                                                    Publisher
MAP        Linker map file
MAP        Map file (usually created by compilers)
MAP        Map                                      Atlas MapMaker
MAP        Network map                              AccView
MAP        Game map for Duke Nukem 3D
MAR        Assembly program                         VAX Macro
                                                    MSN Explorer (possibly
MAR        Microsoft ARchive                        other Microsoft products
                                                    too)
                                                    Mozilla Updater (used to
MAR        Mozilla ARchive                          house binary updates to
                                                    products)
MAS        SmartMaster set                          Freelance Graphics
MAT        Data                                     MATLAB
MAT        Microsoft Access Table                   Microsoft Access
MAX        MAX source code file
MAX        Pfaff Embroidery Format                  Embroidermodder
MB         Memo field values for database           Paradox
MBK        Multiple index file backup               dBASE IV
MBP        Metadata                                 .mobi (Mobipocket)
MBR        Master Boot Record File                  GRUB
MBX        Mailbox data                             Eudora/ZERBERUS
MCA        Minecraft "Anvil" world format           Minecraft 1.2 and onward
MCC        Configuration file                       Mathcad
MCD        MathCad file                             MathCad
MCF        Font file                                Mathcad
MCF        Photo book or photo calendar layout file FotoInsight Designer
MCF        Multimedia Container Format (predecessor
           of Matroska)
MCI        MCI command script                       Media Control Interface
MCL        Multi Edit macro library                 Multi Edit
MCL        Cartesian manipulator for laser systems
MCP        Application script                       Capsule
MCP        Printer driver                           Mathcad
MCR        Minecraft saved world "region" file      Minecraft (up to 1.1)
MCW        Text file                                MacWrite II
MD         Archive                                  mdcd10.arc
MD         Markdown-formatted text file             Markdown
MD2        Quake 2 Model File                       id Software
MD3        Quake 3 Model File                       id Software
MD5        Doom 3 and Quake 4 Model File            id Software
MD5        MD5 checksum                             md5sum, Total Commander
MDA        Data                                     Microsoft Access
MDA        Microsoft Access system database         Microsoft Access
MDB        Microsoft DataBase                       Microsoft Access
           Media Descriptor File, binary files in
MDF        which the actual disc (CD/DVD) data is   Alcohol 120%
           stored
MDF        Master Data File, a Microsoft SQL Server Microsoft SQL Server
           file type
           Measurement Data Format, a binary file   automotive industry,
MDF        format for vector measurement data       developed by Robert Bosch
                                                    GmbH
           Document save in high-resolution,
MDI        created by MSOffice to scan documents    Microsoft Office
           (OCR) and turn them into a .DOC
MDL        Model                                    3D Design Plus or Simulink
MDL        Spreadsheet                              CA-Compete!
MDL        GoldSrc Model File (Quake-Based Engine)  Valve Corporation
MDL        Source Engine Model File                 Valve Corporation
MDL        Quake 1 Model File                       id Software
MDL        Nintendo GameCube Luigi's Mansion Model  Nintendo
MDM        Modem definition file                    TELIX
MDMP       Mini dumpfile
MDR        Microdrive file                          ZX Spectrum emulator by
                                                    g.a.lunter
MDS        Midi Session                             Sound Imp.
MDT        Data table                               Microsoft ILink incremental
                                                    linker
MDX        Multiple index file                      dBASE IV
MDZ        Text description of music module         Cubic Player  Cross-View
ME         MultiEdit configuration                  MultiEdit
ME         Text file READ.ME
MEB        Macro Editor bottom overflow file        WordPerfect Library
MEC        MECCA source                             Maximus
MED        Macro Editor delete save                 WordPerfect Library
MED        Music format                             MED/OctaMED
Mediawiki  Wiki markup                              most wikis
MEM        Macro Editor macro                       WordPerfect Library
MEM        Memory variable save file                dBASE IV  FoxPro  Clipper
MEM        Memos datafile                           Clarion
MEM        Mnemosyne database                       Mnemosyne; other spaced
                                                    repetition software
MEQ        Macro Editor print queue file            WordPerfect Library
MER        Macro Editor resident area (vakioalue)   WordPerfect Library
MES        Macro Editor work space file             WordPerfect Library
MES        Message
MET        Document                                 Omnipage Pro
MET        Macro Editor top overflow file           WordPerfect Library
MET        OS/2 graphics metafile                   PICVIEW.EXE
MEU        Menu group                               DOS Shell
MEX        Macro Editor expound file                WordPerfect Library
MEX        MEX file (executable command)            Matlab
MF         Metafont file                            TeX
MFA        Source code file                         Multimedia Fusion 2 / The
                                                    Games Factory 2
MFF        MIDI                                     Cakewalk, MTPro 4
MFM        Music format                             DMP
MGF        Font                                     Micrografx
MGF        Materials and Geometry Format
MGX        Designer 4.1 Drawing                     Designer 4.1
MHT        Web Archive Single File
MIB        Snmp MIB file
MID        Standard MIDI file                       music synthetizers, Winamp
MIDI       See MID
MIFF       Magick Image File Format
MII        Datafile                                 MicroStat-II
MIME       Message in MIME format (RFC822)
           Nintendo proprietary MIDI file format
miniUSF    for the Reality Signal Processor         Nintendo 64 games
           (Nintendo 64)
MIO        MyInfo topic                             Milenix MyInfo
MIS        Mission, used by many games
MIT        Mitsubishi Embroidery Format             Embroidermodder
MIX        Object file                              Power C
MJS        JavaScript Module
MK         Makefile
MKE        Makefile                                 Microsoft Windows SDK
MKG        Makefile
MKI        Graphics format (Japan MKI)
MKI        Japanese graphics MAKIchan format        MagView 0.5
MKS        Data                                     TACT
                                                    Media Player Classic,
MKV        Matroska Multimedia Container            Windows Media Player,
                                                    Matroska Splitter
ML3        Project                                  Milestones 3.x
MLB        Macro library file                       RT-11, Symphony
MLI        3DS Materials Libraries                  3D Studio
MLRAW      Data                                     Moonlight Creator RAW
                                                    format 3D object
MLV        LabVIEW MathScript
                                                    MultiMate Advantage II,
MM         Text file                                FreeMind mind map file
                                                    (XML)
MM         Source code                              Objective-C++
MMF        Mail message file                        Microsoft Mail
MMM        Multimedia movie file, RIFF RMMP format  MacroMind Director 3.x
MMO        Memo writer file                         RapidFile
MMP        Output video format from Bravado board
MN         MuPAD Pro Notebook                       Workspace file of MuPAD
                                                    (integrated in Matlab)
MND        Menu source                              AutoCAD Menu Compiler
MNG        Map                                      DeLorme Map'n'Go
MNT        Additional (FPT) menu description file   FoxPro
MNT        Menu memo                                FoxPro
MNT        Surface metrology or image analysis      MountainsMap
           document
MNU        Advanced macro file                      HP NewWave
                                                    AutoCAD Menu Compiler 
MNU        Menu                                     Norton Commander 
                                                    Signature
MNU        Microsoft Mouse menu (for DOS apps)
MNX        Compiled menu file                       AutoCAD
MNX        Main (DBF) menu description file         FoxPro
MNY        Account book                             Microsoft Money
MO         Language file                            Sundry
MO?        Packed mail                              FTN software
MOB        Device definition file                   PEN Windows
MOBI       eBook                                    Mobipocket, Kindle
MOD        AMPL model file                          AMPL
MOD        Modula language source
MOD        MODULA-2 source code file                Claridiv id="MDZ"> MDZon
                                                    Modula-2
MOD        Module—used by Windows for DLL which     Win
           implement DOS support
MOD        Music format (Amiga module)              DMP  ST  MDP  VP
MODULES    Module                                   GTK+
MOL        MOD4WIN PlayList                         Mod4Win
MOL        MDL Molfile                              RasMol
MOL2       Tripos Sybyl MOL2 Format                SYBYL, RasMol
MON        SYSGEN monitor build procedure           RT-11
MON        Monitor description                      ReadMail
MOP        MOPAC input file                         MOPAC, RasMol
MOV        Animation format (Mac)                   QuickTime
MOV        Movie file                               AutoCAD AutoFlix
MP2        Mpeg audio file                          Winamp, xing
MP3        MPEG audio stream, layer 3               AWAVE, CoolEdit(+PlugIn),
                                                    Winamp, many others
MP4        multimedia container format, MPEG 4 Part Winamp
           14
MPA        MPEG audio stream, layer 1,2,3           AWAVE
MPC        Calendar file                            Microsoft Project
MPC        Musepack audio
MPEG       multimedia containter format, video,     MPEG Player, Winamp
           audio
MPG        see MPEG
MPKG       Multipackage installer script            Mac OS X
MPL        MediaRack Midi Playlist                  MediaRack
MPM        MathPlan macro                           WordPerfect Library
MPP        Project file                             Microsoft Project
MPPZ       MagicPlot project file                   MagicPlot
MPQ        Mo'PaQ Archive                           Blizzard games
MPR        Generated executable menu file           FoxPro
MPR        Multilizer 5.x and 6.x localization      Multilizer
           project file
MPR        Command & Conquer: Red Alert 2 map file  Red Alert 2
MPT        Bitmap graphics (Multipage TIFF)
MPV        View file                                Microsoft Project
MPX        Compiled executable menu file            FoxPro
MPX        Video format
MPZ        Miradi Project Zipfile                   Miradi
MQ4        MetaQuotes Language 4 (MQL4) source code MetaTrader 4
           file
MQ5        MetaQuotes Language 5 (MQL5) source code MetaTrader 5
           file
MQH        MetaQuotes Language (MQL4 or MQL5)       MetaTrader 4, MetaTrader 5
           header file
MRB        Multiple Resolution Bitmap graphics file Microsoft C/C++
MRC        mIRC file                                mIRC
MRK        Windows User Benchmark                   Win95
MRS        Macro Resource file                      WordPerfect for Win
MS         Microsoft antivirus report               MSAV
MSC        Microsoft C makefile
MSC        management saved console^[1]             Microsoft; Microsoft MMC^
                                                    [2]
MSD        Secure and Encrypted File                mysecuredelivery/Download
MSDL       Manchester Scene Description Language
MSDVD      Windows DVD Maker Project                Windows DVD Maker
MSE        Set file                                 Magic Set Editor
MSG        Message base (e.g. HMB)
MSG        Message text file (ASCII)                Microsoft Outlook
MSG        ZVoice digitized voice file
MSI        Windows Installer Package                Windows Operating Systems
MSO        Microsoft Word OLE Web Page Storage      Microsoft Office
           Stream
MSO        Microsoft Outlook metadata for a         Microsoft Outlook
           Microsoft Word 2000 email attachment^[3]
MSP        Bitmap graphics file                     Microsoft Paint
MSP        Windows Installer Patch                  Microsoft Windows
                                                    Microsoft Producer (for
MSPRODUCER Media Project                            Microsoft PowerPoint XP/
                                                    2003) Project
MSQM       data                                     Microsoft Message Queuing
                                                    National Instruments for NI
MSN        Project                                  MultiSim-Electronic Circuit
                                                    simulator
MSS        Manuscript text file                     Perfect Writer  Scribble 
                                                    MINCE  Jove
MST        Document                                 MS Test
MST        Minispecification file                   Prosa
MST        Setup script file                        Microsoft Windows SDK
MSW        Text file                                Microsoft Word
MSX        CP/M archive                             MSX
MTH        Math file                                Derive
MTL        Wavefront
MTM        Music format                             MultiTracker
MTS        Master Track Pro Files                   MTPro 4
MTS        data                                     EA Sports F1 series, car
                                                    physics
MTS        MPEG 2 Transport Stream                  Various media playback
                                                    devices / software
MTV        MTV Ray Tracer graphic file
MTW        Datafile                                 Minitab
MU         Quattro pro for DOS Menu definition file Quattro Pro
MUI        Multilingual User Interface
MUM        MATLAB CAPE-OPEN Unit Operation Model    Matlab
           file
MUM        Microsoft update file                    Microsoft
MUS        Finale music document                    Finale
MUS        Music format (MIDI in Doom)
MUS        Sound file                               MusicTime
MUZ        Hover Game MIDI File                     Windows' Hover! Game^[4]
MVF        Stop frame file                          AutoCAD AutoFlix
MVI        Movie command file                       AutoCAD AutoFlix
MVO        Data                                     Mad Virgin 3D object
MVW        Log file                                 Saber LAN
MWF        Animation                                ProMotion
MWS        MWave DSP synths instrument              AWAVE
MXF        Material exchange format (RFC 4539,
           SMPTE 377M)
MXL        PackRat 5.0 support DLLs                 PackRat 5.0
MXM        Material                                 Maxwell Render
MXP        Adobe Extension File                     Adobe Dreamweaver and Adobe
                                                    Flash
MXP        3ds Max Configuration File               3ds Max
MXP        MasterCook exported recipe
MXT        Data                                     Microsoft C
MYD        a MyISAM data file in MySQL              MyISAM, MySQL
MYI        a MyISAM index file in MySQL             MyISAM, MySQL
MYP        Presentation                             MM Make Your Point
MZ         Binary-format Map                        MazeEdit
MZE        Text-format Map                          MazeEdit
MZG        Binary-format Map Collection             MazeEdit
MZX        Binary-format Encrypted Map              MazeEdit

NAM     Name Space Modules                        Novell NetWare
NAP     Naplps file (VideoShow)                   EnerGraphics
NAPLPS  North American Presentation Layer
        Protocol Syntax
NB      Text file                                 Nota Bene
NB      Wolfram Mathematica Notebook (see Wolfram Mathematica
        Language)
NBF     Nokia Backup File                         Nokia Mobile Phones
NBS     Minecraft Note Block Studio file          Minecraft Note Block Studio
NBU     Nokia Backup                              Nokia Suite
NC      Binary Data                               netCDF software package
NC      Instructions for NC (Numerical Control)   CAMS
        machine
NC      Name code program                         namec-git/namec software
                                                  package
NC      Non-error checking preprocessed Goc       Geoworks
        source code
NCC     CNC (Computer Numeric Control) control    CamView 3D
        file
NCD     NC Drill File (Excellon Format, printed   Most PCB layout software
        circuit board hole definitions)
NCD     Norton Change Directory support file      Norton Commander
NCP     Re-volt Collision file                    Re-volt
        NetConnect data file. Contains
ND      information on multi-user access to the   Intuit QuickBooks
        company file.
NDB     Network database                          Intellicom - Compex
NDS     Nintendo DS ROM file used for Homebrew    Nintendo DS
        and commercial (Game) files on DS
NDL     Nodelist file
NDX     Index file                                dBASE II - III - IV - dBFast
NEF     Nikon RAW image format                    Nikon cameras
                                                  학교생활기록부 작성 프로그램
NEIS    Korean Student Record Document            (Student Record Writing
                                                  Program)
NEO     Raster graphics file                      Atari Neochrome
NES     iNES ROM image format
NET     Network configuration/info file
NEU     Pro/Engineer neutral file format          PTC Pro/Engineer
netCDF  Network Common Data Format
NEW     Ameco Embroidery Format                   Embroidermodder
NEW     New info
NFF     Haines Neutral File Format
NFF     WorldToolKit Neutral File Format
NFO     Folioview database
NFO     Help format                               Nextpage Folio
NFO     Info file                                 Compact NFO Viewer
NG      Hypertext Database                        Norton Guide
NGC     G-Code file                               Inkscape G-Code tools
                                                  extension
NGO     NG linker object file                     NGML
NGS     NG compiler source file                   NGC
NIF     netimmerse/gamebyro file
NIL     NIL                                       Icon Hear-It
NITF    National Imagery Transmission Format
NK2     e-mail address autocomplete archive       Microsoft Office Outlook
NL      Norton Desktop Icon Library
NLM     Netware loadable module                   Novell Netware
NLS     National Language Support file            MS-DOS
NLX     Form                                      FormWorx 3.0
nmf     Node Map File                             Used by SpicyNodes
nnn     Arj archive volumes up to 999             ARJ
nnn     Netware unicode rule table (e.g.          Novell Netware
        1250_Uni.036)
nnn     News about smth with ext. of ver. number
nnn     RAR archive volumes up to 999             RAR
NOT     Notation
NOT     Yard Notes File                           FYM
NOTE    Notability Note File                      Notability
NP      Project schedule (Nokia Planner)          Nokia Planner
NPI     Source for DGEN.EXE interpreter           dBASE Application Generator
NPJ     Nile Project                              Game Mission Editor
NPR     Nuendo Project File                       Steinberg Nuendo
NRG     Nero Disc Image File                      Nero Express / Burning ROM
NRW     Nikon Coolpix RAW image                   Nikon
NSA     media                                     Nullsoft Streaming Audio
NSF     database                                  Lotus Notes
NSF     Music module                              NES Sound File
NSS     Norton screensaver module                 NC - NDW Screen Saver
NST     Music module                              Amiga Noise Tracker
NSV     media                                     Nullsoft Streaming Video
NSX     Compound index file                       SuccessWare SIX 3.00
NT      Startup files                             Windows NT
NT3     BAHN Layout file                          JBSS BAHN
NTF     database design template                  Lotus Notes
NTH     Nokia Theme File                          Nokia PC Suite
NTR     Executable ASCII text file (strip header  netrun31.zip
        and rename)
NTS     Executable ASCII text file (strip header  netsend1.zip
        and rename)
NTS     Tutorial                                  Norton
NTX     Database index file                       Clipper 5
NUF     Message for new users on their 1st call   Procomm Plus
NUG     Video Nugget                              CBT Nuggets
NUMBERS Numbers spreadsheet file                  Numbers
NV      NewViews DOS accounting database          QW Page NewViews
NV2     NewViews accounting database              QW Page NewViews
NWC     Note Worthy document                      Note Worthy
NWS     Info text file (latest news) (ASCII)
NXT     Sound (NeXT format)

O$$          Outfile                             Sprint
O            Object file                         UNIX - Atari - GCC
O01          Typhoon vOice file                  AWAVE
OAZ          Fax                                 NetFax Manager
OB           Object cut/paste file               IBM LinkWay
OBD          Microsoft Office Binder             MSOffice
OBJ          Compiled machine language code
OBJ          Object code                         Intel Relocatable Object
                                                 Module
OBJ          Wavefront Object
OBJF         Data                                Triangle strips object
OBR          Object browser data file            Borland C++
OBS          Script                              ObjectScript
OBT          Microsoft Office Binder Template    MSOffice
OBV          Visual interface                    ObjectScript
OBZ          Microsoft Office Binder Wizard      MSOffice
OCF          Object Craft File                   Object Craft
OCD          OCAD Map File                       OCAD
OCR          Incoming fax transcribed to text    FAXGrapper
OCT          Musical file                        Octalizer
OCX          New Custom Control's format in VB   Visual Basic
             4.0
OCX          OLE custom control
ODB          OpenDocument database               LibreOffice Base
ODC          Microsoft Office Data Connection
ODF          OpenDocument formula                LibreOffice Math
ODG          OpenDocument drawing                LibreOffice Draw
ODIF         Open Document Interchange Format
ODL          Object Description Language
ODL          Type library source                 Visual C++
ODM          OpenDocument master document        LibreOffice Writer
ODP          OpenDocument presentation           LibreOffice Impress
ODS          OpenDocument spreadsheet            LibreOffice Calc
ODT          OpenDocument text document          LibreOffice Writer
                                                 Microsoft e-mail software:
OEACCOUNT    XML format, account files           Outlook Express, Windows Mail,
                                                 Windows Live Mail, Microsoft
                                                 Outlook
OFD          Form definition                     ObjectView
OFF          Object File Format vector graphics
             file
OFF          Object File Format vector graphics
OFM          PostScript font description file
OFN          Microsoft Office documents          Microsoft Office
OGG          Ogg multimedia container format
OHB          Source                              On Hand Basic
OHS          Outbound History                    Bink/+
OIF          QuickBase file format
OKT          Music (8 channels)                  Oktalyzer
OKT          Music format                        Oktalyzer
OLB          Object library                      VAX
OLD          Backup file
OLI          Text file                           Olivetti
OLK14CONTACT olk14_contact                       Microsoft Outlook
OLM          Outlook for Mac Data File           Microsoft Outlook for macOS
OLSR         Configuration file                  olsrd
OMA          Audio file                          Labelgate CD 2, MAGIQLIP2
OMF          Open Media Framework                Avid Media Composer
OMG          Audio file                          Sony compressed audio file
                                                 (ATRAC3)
ONE          OneNote Section                     Microsoft OneNote
ONEPKG       OneNote Single File Package         Microsoft OneNote
ONETOC       OneNote 2003 Table Of Contents      Microsoft OneNote
ONETOC2      OneNote Table Of Contents           Microsoft OneNote
OOF          Data                                Outrage 3D Object Format
                                                 (Descent)
OOG          Data                                WEBOOGL 3D object
OOM          Swap file                           Shroom
OPJ          Origin Project File                 Origin version 4.1 and later
OPN          Active options                      Exact
OPT          Options                             name used by many programs for
                                                 configuration information
OPT          Delphi project options              Borland Delphi
OPT          Optimize support file               QEMM
OPUS         Ogg/Opus audio file                 mpv, mplayer, many others (
                                                 official file format).
OPW          Organization chart                  Org Plus for Windows
OPX          Inactive options                    Exact
OR2          Calendar file                       Lotus Organizer
OR3          Calendar file                       Lotus Organizer
OR4          Calendar file                       Lotus Organizer
OR5          Calendar file                       Lotus Organizer
OR6          Calendar file                       Lotus Organizer
ORA          Parameter file                      Oracle
ORC          Orchestra MIDI file                 CSound
ORG          Calendar file                       Lotus Organizer
ORG          Older Origin Project                Origin versions 4 or earlier
OSB          osu! storyboard                     osu!
OSC          OpenStreetMap Changeset             OpenStreetMap
OSK          osu! skin                           osu!
OSR          osu! replay                         osu!
                                                 Microsoft e-mail software:
OST          Offline Storage Table               Outlook Express, Microsoft
                                                 Outlook
OSU          osu! beatmap                        osu!
OSZ          osu! beatmapset                     osu!
OTG          OpenDocument drawing template       LibreOffice Draw
OTB          Over-the-air bitmap graphics
OTF          Subtitle font information for media Media players / software which
             content                             support PGS subtitling
OTH          OpenDocument HTML document template LibreOffice
OTL          Outline font description            Z-Soft Type Foundry
OTL          Ventura Publisher's Type Foundry
             Outline Editor format
OTL          The Vim Outliner                    A vim plugin
OTP          OpenDocument presentation template  LibreOffice Impress
OTS          OpenDocument spreadsheet template   LibreOffice Math
OTT          OpenDocument text document template LibreOffice Writer
OTX          Text file                           Olivetti Olitext Plus
OUT          Output file
OUT          Design II for Windows Output file
             Open Virtualization Format package
OVA          for packaging and distributing
             virtual appliances
OV1          Overlay file (part of program to be
             loaded when needed)
OV2          Overlay file (part of program to be TomTom Point of Interest
             loaded when needed)
OVD          Datafile                            ObjectVision
             Open Virtualization Format
OVF          descriptor file, an XML file which
             describes the virtual machine
             packed inside an OVF package
OVL          Overlay file (part of program to be
             loaded when needed)
OWL          Web ontology language (OWL) file    Protégé and other ontology
                                                 editors
OXT          OpenOffice.org extension            OpenOffice.org / LibreOffice

P          Database PROGRESS source code      PROGRESS
P          PASCAL source code file
P          Parser source code file
P          Picture file                       APPLAUSE
P          Rea-C-Time application parameter   ReaGeniX code generator
           file
P0?        Split archive UC2                  SAS.EXE
P10        Tektronix Plot                     GCGW
P10        Certificate Request
P12        Personal Information Exchange      "Crypto Shell Extensions"
P12        Another variant of the PFX
           extension
P16        Music (16 channels)                ProTracker Studio 16
P22        Patch file (Patch22)               Patch22
P80        PLM-80 source
P86        PLM-86 source
           Backupfile of a project in
p2v        eventplanning software plan2viz
           (windowsbased)
P3T        PlayStation 3 Theme file           PS3 Theme settings menu
PA1        Worktable                          PageAhead
PAC        SBStudio II Package or Song        SBStudio II
PAC        STAD Image (graphics ?)
PACK       ?                                  ?
PACKAGE    Contents                           The Sims 2 - Spore - The Sims 3
PAD        Automatic print definitions        Produa
PAD        Keypad definition                  Telemate
PAF        For Personal Ancestral File data
           files
PAGES      Pages document file                Pages
PAK        Archive                            Pak
PAL        Paint Shop Pro color palette (JASC PaintShop Pro, XnView
           format)
PAL        Palette file (RIFF format)         Microsoft Draw - Win. Paintbrush
                                              - XnView- many
PAL        Palette file                       Diablo II
PAM        PAM Portable Arbitrary Map         Netpbm
           graphics format
PAN        Printer-specific file (copy to     CorelDRAW
           coreldrw.ink)
PAR        Parameter file                     Fractint
PAR        PARTS application                  Digitalk PARTS
PAR        Permanent output file              Windows 3.x
PAR        Parity Archive
PAR2       Parity Archive v2
PART       Part of a download file
PAS        Pascal language source             Borland Pascal
PAT        Gravis Ultrasound Patch            Convert (c) Villena
PAT        Hatch patterns                     AutoCAD - Photostyler
PAT        Vector fill files                  CorelDRAW
PAT        Pattern File                       Photoshop
PAT        GIMP pattern
PB         Fax                                FAXability Plus
PB         Phonebook                          WinFax Pro
PB         Proboard Conf. files               Proboard
PB         Setup file                         PixBase
PB1        Document                           First Publisher for Windows
PBA        Powerbasic BASIC source code       Genus
PBD        Phone book                         FaxNOW! - Faxit
PBD        Molecule (protein data bank)
PBI        Powerbasic include file            Genus
PBI        Profiler Binary Input              Microsoft Source Profiler
PBK        Microsoft Network Phone book       MSN
PBL        Powerbasic library                 Genus
PBLIB      Power Library                      PowerBASIC
PBM        PBM Portable Bit Map graphics      Jasc Media C
           format
PBM        Planar bitmap graphics             XLib
PBO        Profiler Binary Output             Microsoft Source Profiler
PBO        A file type used by Bohemia        Arma 3, PBO Manager
           Interactive
PBT        ProBoards Theme ^[5]               ProBoards remotely hosted
                                              message boards
PBT        Profiler Binary Table              Microsoft Source Profiler
PC         Text file containing IBM PC
           specific info
PC3        Custom palette                     Harvard Graphics 3.0
PC8        ASCII text IBM8 character set      NewWave Write
PCA        Perfect Clarity Audio              Sony Vegas Pro
                                              P-CAD, PCBExpress, and other P
PCB        P-CAD database                     rinted Curcuit Board design
                                              software
PCB        Artwork design file (Circuit board Zuken CadStar
           design)
PCC        Cutout picture vector graphics     PC Paintbrush
PCD        Graphics format (Kodak Photo-CD)
PCD        Kodak Photo-CD Image graphics file hpcdtoppm
           (768x512)
PCD        Pfaff Embroidery Format            Embroidermodder
PCF        Pixel Coordination Format
PCH        Patch file
PCH        Precompiled header                 Microsoft C/C++
PCJ        Multimedia authoring tool graphics IBM's Linkaway-Live
           file
PCK        Pickfile                           Turbo Pascal
PCL        HP-PCL graphics data file          HP Printer Command Language
PCL        Old Pencil Animation File PCL      Pencil2D
PCLX       Pencil Animation File PCLX         Pencil2D
PCM        OKI MSM6376 synth chip PCM         AWAVE
PCM        PCM                                Authorware
PCM        Pfaff Embroidery Format            Embroidermodder
PCQ        Pfaff Embroidery Format            Embroidermodder
PCS        Microsoft PowerPoint picture       Microsoft PowerPoint - Microsoft
           package                            ClipArt Gallery
PCS        PCSurvey file                      PCSurvey by Softart - Land
                                              Surveying Software
PCS        Pfaff Embroidery Format            Embroidermodder
PCT        Bitmap graphics file               Macintosh b&w PICT1 - color
                                              PICT2
PCW        Text file                          PC Write
PCX        PC paintbrush bitmap format        QPeg - Display - ZSoft - PC
                                              Paintbrush, XnView
PDA        Bitmap graphics
PDB        Packrat 5.0 data file              Packrat 5.0
PDB        container format (envelope) for    Palm OS, Garnet OS, Access Linux
           Palm OS databases                  Platform, e-book
PDB        debugging data                     Microsoft Windows
PDB        Molecule (protein data bank)
PDD        Adobe Photoshop Elements Image     Adobe Photoshop Elements
PDE        Pathology Data Exchange
PDE        data                               PowerDesk Encrypted
PDE        source code file                   Processing programming language
PDF        Adobe's Portable Document Format   Adobe Acrobat Reader
PDF        Graphics file (ED-SCAN 24bit
           format)
PDF        Package Definition File
PDF        PCAD Database Interchange Format   Pdifin.exe - Pdifout.exe
PDF        Print device information Netware
PDG        Print Shop Deluxe data file
PDI        Portable Database Image
PDI        Protected Digital Identity         SertintyONE
PDL        Project Description Language file  Borland C++ 4.5
PDM        Program                            Deskmate
           PowerDesigner's physical data
PDM        model (relational model) file      PowerDesigner
           format
PDM        Visual Basic (VB) Project          Visual Basic
           Information File
PDN        Image file                         Paint.NET
PDS        PALASM Design Description
PDS        Pds graphics
PDS        Planetary Data System Format
PDS        Pldasm source code file (hardware
           assembly)
PDV        Printer driver                     Paintbrush
PDW        Document                           Professional Draw
PEB        Program Editor bottom overflow     WordPerfect Library
           file
PED        Program Editor delete save         WordPerfect Library
PEM        Program Editor macro               WordPerfect Library
           A text-based certificate file      Applications that need to use
PEM        defined in RFC 1421 through RFC    cryptographic certificates,
           1424^[6]                           including web-servers
PEQ        Program Editor print queue file    WordPerfect Library
PER        Program Editor resident area       WordPerfect Library
PES        Program Editor work space file     WordPerfect Library
PET        Program Editor top overflow file   WordPerfect Library
pet        package^[7]                        Puppy Linux
PEX        Proboard EXecutable file (Executed Proboard
           from PB)
PFA        PostScript Font File
PFA        Type 3 font file (unhinted
           PostScript font)
PFB        Adobe Acrobat document             Adobe Acrobat Reader
PFB        PostScript font                    Adobe Type Manager (ATM)
           (Personal Filing Cabinet) contains
PFC        e-mail, preferences and other      AOL
           personal information
PFC        Text file                          First Choice
PFK        Programmable function keys         XTreePro
PFM        PostScript Type 1 font metric file Microsoft Windows, Adobe Acrobat
                                              Reader
PFM        Windows Type 1 font metric file
PGN        Portable Game Notation -Text       Most chess playing computer
           specification for Chess game       applications
PFS        Database (PFS:FILE) - text file    PFS
           (PFS:Write)
PFT        Printer font                       ChiWriter
                                              Applications that need to use
PFX        An encrypted certificate file^[6]  cryptographic certificates,
                                              including web-servers
PG         Page cut/paste file                IBM LinkWay
PGD                                           PGP cripted disk
PGI        Printer Graphics File device       PGRAPH library
           driver
PGL        HP Plotter vector graphics format
PGM        Graphics format (Portable GrayMap) JASC Media C
PGM        Program                            Signature
PGP        Support file                       Pretty Good Privacy RSA System
PGS        Manual page                        man4dos
PH         Optimized .goh file                Geoworks
PH         Perl header file
PH         Phrase-table                       Microsoft C/C++
PHD        PolyHedra Database
PHM        Phone book                         DN - Lync
PHN        Phone list                         UltraFax - QmodemPro
PHO        Phone database                     Metz Phone for Windows
PHP        PHP file
PHP3       PHP 3 file
PHP4       PHP 4 file
PHF        Database File                      Nuverb Systems Inc: Donarius
PHR        Phrases                            LocoScript
PI2        Portrait Innovations High          Portrait Innovations Studio2
           Resolution Encrypted Image file    (proprietary)
PIC        123 Vector graphics format         CShow - Alchemy - Paint (Pictor)
PIC        Bitmap graphics file               Macintosh b&w PICT1 - color
                                              PICT2
PIC        Lotus picture
PIC        PIXAR picture file                 SDSC Image Tool
PICT       Macintosh Picture
PIE        GlovePIE script file               GlovePIE
PIF        OS/2 graphics metafile             PICVIEW.EXE
PIF        Program Information File           Windows 3.x, 9x, NT
PIF        Vector graphics GDF format file
           (IBM mainframe computers)
PiM        Pascal Text Mode Image File        The Ultimate Draw
PIPE       PIPE-FLO project design file       PIPE-FLO Professional
PIT        Compressed Mac file archive        unpackit.zoo
           created by PACKIT
PIT        Partition Information Table for    Odin3
           Samsung's smartphone with Android
PIT        File used to connect to a remote   Dell (previously Quest)
           system.                            vWorkspace
PIV        Pivot Stick Animator file          Pivot Stick Animator
PIX        Alias image file                   SDSC Image Tool
PIX        Inset Pix
PJ         Project                            CA-SuperProject
PJT        Additional (FPT) project           FoxPro
           description file
PJX        Main (DBF) project description     FoxPro
           file
PK         PacKed bitmap font bitmap file
           (TeX DVI drivers)
PK         Peak file                          Cool Edit
PKL        Pickle file                        Python object serialization
PK2        Quake 2 data file                  id Software
PK3        Quake 3 data file                  id Software
PK4        Doom 3 and Quake 4 data file       id Software
PKCS12     Another variant of the PFX
           extension
PKA        Archive                            PKARC
PKG        Installer script                   Next, Mac OS X, Sony PS3
PKG        P-CAD database                     P-CAD
PKPASS     Wallet pass                        Apple Wallet
PKT        Fido message packet                FTN software
PL         Palette                            Harvard Graphics
PL         Perl source code file
PL         Prolog source code file
PL         Property List font metric file     TeX
PL         IRAF pixel list                    IRAF astronomical data format
PL1        Room plan                          3D Home Architect
PL1        PL/I source file                   PL/I compilers
PL2        Palette                            Diablo II
PL3        Chart palette                      Harvard Graphics 3.0
PLA        Playlist
PLANTUML   UML Diagram (also PU)              PlantUML
PLB        FoxPro library                     FoxPro
PLB        P-CAD library                      P-CAD
PLC        Add-in file (functions - macros -  Lotus 1-2-3
           applications)
PLC        P-CAD database                     P-CAD
PLD        PhotoLine Document                 PhotoLine image processing
PLE        Encrypted Chat Log                 Messenger Plus! Live Plugin -
                                              Log viewer
PLI        PL/I source file                   PL/I compilers
PLIST      Mac OS Property List, also used on Apple's Property List Editor
           iOS, NeXTSTEP, and GNUstep
PLL        Prelinked library                  CA Clipper
PLM        DisorderTracker2 music module      AWAVE
PLN        Spreadsheet                        WordPerfect for Win
PLP        Playlist
PLP        Messenger Plus! Sound Pack         Messenger Plus! Live Plugin
PLS        Playlist file                      WarpVision (OS/2)
PLSC       Messenger Plus! Script Pack        Messenger Plus! Live Plugin
PLSK       Messenger Plus! Skin Pack          Messenger Plus! Live Plugin
PLT        HPGL plotter file vector graphics  AutoCAD
PLT        Output file for ploter
PLT        P CAD: Output file editor for      P CAD
           PCPLOT or PCPRINT
PLT        Page Magic 2.0 paper format        Page Magic 2.0
PLT        Palette
PLT        Table for .pll                     CA Clipper
PLUGIN     Plug-in                            macOS
PLY        Data                               PopMail
PLY        Presentation screen                Harvard Spotlight
PLY        ZipPack
PLY        Polygon File Format or the         3D Scanners
           Stanford Triangle Format.
PLY2       Data                               PLY2 object
PM         Auran Jet progressive mesh file    Trainz
           (obsoleted by IM and LM)
PM         Perl module
PM         Bitmap graphics                    Presentation Manager
PM3        PageMaker 3.0 data file            PageMaker 3.0
PM4        Document                           PageMaker 4
PM5        Aldus PageMaker 5.0 publication    Aldus PageMaker
PMA        PMarc Archive
PMC        Graphics                           A4TECH Scanner
PMI        OS/2 V3 SVGA PMI-File              Svga.exe
PMI        PhatPad note                       PathWare
PMM        Program file                       Amaris BTX/2
PMP        PhotoMorph Project                 PhotoMorph
PN3        Printer device driver              Harvard Graphics 3.0
PNG        Portable Network Graphics
PNCL       Pinnacle file                      Pinnacle by Optys Tech
                                              Corporation
PNF        Pre-compiled Setup Information     Microsoft Windows
           file
PNM        PBM Portable aNy Map graphics file
PNT        Macintosh painting
PNT        Pointlist segment                  FTN software
PNT        QWK reader pointer file            MarkMail 2.x
POD        UNIX perldoc File ("Plain Old      pod2man, pod2html
           Documentation")
POF        Altera FPGA programming file       Altera Quartus
           (External Flash)
POH        Optimized .goh file                Geoworks
POL        InnovMetric Software Polygon
           Models Format
POLICY     Group Policy File                  Microsoft Windows
POLY       Data                               Patrick Flynn's Poly Format - 3D
                                              object
POP        Messages index                     PopMail
POP        Pop-up menu object                 dBASE Application Generator
POT        Microsoft PowerPoint template
POV        Raytraced graphics image           Persistence Of Vision
POW        Power Chords instrument/song file  Power Chords
PP         Amiga archive                      POWERPACKER
PPA        Microsoft PowerPoint Add-in
PPB        Button bar for Print Preview       WordPerfect for Win
PPD        PostScript printer description
           file
PPJ        Premiere Project                   Premiere
PPK        Archive (using for many            PPK
           distributives)
PPL        PolaroidPalettePlus ColorKey       Harvard Graphics 3.0
           device driver
PPM        Graphics format (Portable          JASC Media C.
           PixelMap)
PPO        Preprocessor output                CA Clipper 5.*
PPP        Publication                        PagePlus
PPS        Storyboard                         Personal Producer
PPS        Microsoft PowerPoint Slideshow
           (stand alone slideshow)
PPT        Microsoft PowerPoint Presentation  Microsoft PowerPoint
PPTX       MS Office Open-XML Presentation    Microsoft PowerPoint
PPSX       MS Office Open-XML Auto-Play       Microsoft PowerPoint
           Presentation
PR1        Packrat 4.0 data file              Packrat 4.0
PR2        Packrat 4.x data file              Packrat 4.x
PR2        Presentation                       Aldus Persuasion 2.x
PR2        Printer driver                     dBASE IV
PR3        PostScript printer driver          dBASE IV
PR3        Presentation                       Aldus Persuasion 3.x
PRC        container format (envelope) for    Palm OS, Garnet OS, Access Linux
           Palm OS databases                  Platform, Mobipocket
           "Product Representation Compact",
PRC        for embedding 3D data in a PDF     CAE and CAM applications
           file
PRD        Printer driver
PRE        Presentation                       Freelance Graphics
PRE        Settings                           Programmer's WorkBench,
                                              Microsoft C/C++
PRE        Stork graphic file
PRF        CheckIt Pro v1.0 data file         CheckIt Pro 1.0
PRF        Pixel Run Format graphics file     Improces - Fastgraph
PRF        Printer driver                     dBASE IV
PRF        Profiler output
PRG        Program source code (e.g. Clipper  CA Clipper
           language)
PRG        Program source                     dBASE IV - FoxPro - Clipper 5 -
                                              dBFast
PRG        Program                            Atari
PRI        Printer definitions                LocoScript
PRJ        Borland C++ IDE project file       BC.EXE - BCW.EXE
PRJ        Mkd (Unix command)                 Mkd project file to extract
                                              documentation
PRK        SimPark Saved File                 SimPark
PRM        Parameters
PRN        Printer driver                     Signature
PRN        Text file                          Lotus 1-2-3 - Symphony
PRN        Usually printer output file
PRO        Profile                            used by many programs to store
                                              configuration data
PRO        Graphics profile file              DOS
PRO        Proboard conf. file                Proboard
PRO        Punch! Home Design File            Punch! Home and Landscape
PRO        Prolog language source
PRO        PROLOG source code file
PROJ       Project File (Interface Builder)   NeXT
PROPERTIES Java properties file               Java applications
PROTO      Message specification              Google Protocol Buffers
PRP        Plasma Registry Page               Plasma (engine)
PRR        The Perfect Resume data file       Perfect Resume
PRS        Norton Viewer DLL file
PRS        Presentation                       Harvard Graphics Win
PRS        Printer Resource e.g. fonts        WordPerfect for Win
PRS        Procedure                          dBASE IV
PRT        P-CAD component                    P-CAD
PRT        Part or Drawing                    Cadkey
PRT        Printer driver                     Dr. Halo
PRX        Compiled program                   FoxPro
PS         Document in PostScript format      adobe
PSA        Archive (Pretty Simple Archive)    PSA.OUT (GNU)
PSB        For big Photoshop files            Photoshop Document
PSD        Design II for Windows Process
           Simulation Diagram
PSD        Periscope Debbuger Def file        Periscope
PSD        Photoshop bitmap file              Photoshop document
PSE        PyMOL session^[8]
PSE        Truncated form of PSEG (see below)
PSEG       Bitmap graphics                    IBM printer Page SEgment
PSF        Outline PostScript printer font    ChiWriter
PSM        Music format (Protracker Studio    Protracker - MASI
           Module)
PSM        Symbol table of IDE                Turbo Pascal
PSM        3D Model                           18 Wheels Of Steel
PSM1       Windows Powershell module^[9]      Windows Powershell
PSMODEL    PowerSHAPE Model                   PowerSHAPE
PSN        Presentation file for Sound Script Win
PSP        image file with layers             Paint Shop Pro (all versions)
PSPPALETTE Paint Shop Pro color palette (JASC Paint Shop Pro 8.0 and newer^
           format)                            [10]
PSQ        Premiere Sequence                  Premiere
PST        Postbox file                       BMail
PST        Archive File                       Microsoft Outlook
PSV        PlayStation 2/PlayStation 3 saved  PlayStation 2 and PlayStation 3
           game
PSW        File w/ passwords for any program/ many
           game
PS1        Windows Powershell script^[9]      Windows PowerShell
PT         Game crack                         Player Tools
PT         Kodak Precition Color Management
           System
PT3        Device driver                      Harvard Graphics 3.0
PT3        Template                           PageMaker 3
PT4        Template                           PageMaker 4
PT5        Aldus PageMaker 5.0 publication    Aldus PageMaker
           template
PTB        Power Tab Software                 Power Tab Editor
PTB        Script                             PubTech BatchWorks
PTF        PlayStation Portable Theme file    PSP Theme settings menu
PTF        Pro Tools Session File             Digidesign Pro Tools
PTG        Panasonic Title Graphics
PTL        Premiere Title                     Premiere
PTM        Macro                              PubTech BatchWorks
PTM        Music format
PTM        Page Magic 2.0 template            Page Magic 2.0
PTN        Pattern                            Cadkey
PTN        Pattern                            CarveWright/CompuCarve Designer
           PedFast Technologies Pedigree      The Breeder's Standard, iPed,
PTPED      Database^[11]                      The Cattery's Standard,
                                              Equestrian's Standard
PTR        OS/2 cursor image file             ICONEDIT.EXE
PTR        QWK reader pointer file            QMail
PTU        Performer Terrain Utilities
PTX        Pro Tools 10 session file          Avid Pro Tools
PU         UML Diagram (also PLANTUML)        PlantUML
PUB        Package File                       Exstream Dialogue
PUB        Page template                      Microsoft Publisher
PUB        Public key ring file               Pretty Good Privacy RSA System
PUB        Publication                        Ventura Publisher - 1st
                                              Publisher
PUD        Warcraft II Map file               Warcraft II
PUT        Archive                            PUT
PUT        Graphics format                    WScan
PUZ        Microsoft Publisher "Packed and    Microsoft Publisher, many file
           Go" archive                        archivers with CAB support
PVD        Script                             Instalit
PVK        Private Key File                   Microsoft Authenticode
PVL        Library                            Instalit
PVM        Texture Files                      PVMEdit
PVT        Local Fidonet pointlist            FTN software
PW         Text file                          Professional Write
PWF        Workflow Files                     Mac OS X Server Podcast Producer
PWK        Workspace File                     PolyWorks
PWL        Password List
PWP        Text document                      Professional WritePlus
PX         Paradox 3.0 file                   Paradox 3.0
PXP        3DS Process file                   3D Studio
PXR        Pixiar Picio                       AltamiraComposer
PXZ        Compressed file to exchange media  PSALMO
           elements
PY         Python script file                 Python interpreter
PYC        Compiled Python module             Python interpreter
PYD        Python DLL                         Python interpreter
PYI        Cognos Powerplay Model
PYK        PYK Compressed File                PYK
PYO        Optimized compiled Python module   Python interpreter
PYW        Python Script Without Console      Python interpreter
           Window
PZD        Default settings                   Pizazz Plus
PZI        Graphics format                    PZP
PZO        Overlay file                       Pizazz Plus
PZP        Palette                            Pizazz Plus
PZS        Settings                           Pizazz Plus
PZT        Transfer file                      Pizazz Plus
PZX        Swap file                          Pizazz Plus

Q0   Q0 graphic file
Q3S  Data                                        Quick3D Scene
QAG  Quick Access Group                          Norton Desktop
QAP  Application                                 Omnis Quartz - Omnis Studio
QB   Tony Hawk's Pro Skater series scripting
     files
QBB  Quickbooks Backup File
QBE  Saved query (Query By Example)              dBASE IV - Quattro Pro
QBO  Compiled query                              dBASE IV
QBW  Spreadsheet                                 QuickBooks for Windows
QCH  Qt Compressed Help                          Trolltech Qt Assistant
QCP  Mp3 extension on Motorola ringtones         Motorola Phones
QDF  Data file                                   Quicken data file
QDK  Backup of startup files created by Optimize QEMM
QDn  Data file - segment n                       Omnis Quartz- Omnis Studio
QDV  Graphics file                               Steve Blackstock Giffer
QDR  Configuration file                          Q-Dir
QEF  Query file                                  Q+E for Microsoft Excel
QFP  QUICKfind Server Plug-in                    IDM QUICKfind Server
QFX  Quicken-specific implementation of the OFX  Intuit Quicken
     specification
QFX  Fax                                         QuickLink
QG3  Data                                        QuickMem Greek
QHC  Qt Help Collection                          Trolltech Qt Assistant
QHCP Qt Help Collection Project                  Trolltech Qt Assistant
QHP  Qt Help Project                             Trolltech Qt Assistant
QIF  Quicken Interchange Format                  Intuit Quicken
QIZ  World book quiz                             World Book
QLB  Quick library                               Microsoft C/C++
QLC  ATM Type 1 fonts script                     Adobe Type Manager
QLP  Printer driver                              QuickLink
QM4  Options or services file                    QMail 4.x Mail Door
QPR  Generated query program                     FoxPro
QPR  Print queue device driver                   OS/2
QPX  Compiled executable QBE query file          FoxPro
QRMX Quick Risk Matrix data file                 Quick Risk Matrix by
                                                 Riskfiniti
                                                 QuickReport
QRP  Database report file
                                                 ^[12]

QRS  Equation Editor support file                WordPerfect for Win
QRT  Graphics format (QRT ray tracing)
QRY  Query                                       dBASE IV
QT   QuickTime movie (animation)
QTVR QuickTime VR Movie
QUOX Question Object Document                    Quobject Designer and Quobject
                                                 Explorer
QVD  QlikView Document (Data)                    QlikView Compressed Database
                                                 File
QVW  QlikView Document (View)                    QlikView Presentation File
QWK  QWK reader message file
QXD  Document                                    QuarkXPress
QXL  Element library                             QuarkXPress

R        Ratfor file                                    Ratfor
R        Script file                                    R
R00,     Part of a multi-file RAR archive               RAR
R01, ...
R2D      Reflex 2 datafile                              Reflex 2
R3D      Red Raw Video (raw video data created with a   Red Camera
         Red camera)
R8       Raw graphics file (one byte per pixel) plane   PicLab
         one
R8P      PCL 4 bitmap font file                         Intellifont
RA       Remote Access conf. files                      RA
RA0,     Part of a multi-file RAR archive               RAR
RA1, ...
RAD      2-op FM music                                  Reality AdLib Tracker
RAD      Radiance                                       Radiance
RAL      Remote Access Language file                    Remote Access
RAM      Ramfile                                        RealAudio
RAP      Flowchart                                      RAPTOR
RAR      Archive                                        RAR
RAS      Graphics format                                SUN Raster
RAT      Datafile (RATS)
RAW      HSI raw graphic file
RAW      PCM Signed Raw Sound File
RAW      QRT graphic file
RAY      Rayshade
RB       Ruby Script file                               Ruby Script
RBF      Datafile                                       Rbase
RBXM     ROBLOX "model"                                 ROBLOX
RBXL     ROBLOX "level"                                 ROBLOX
RC       Configuration file                             emacs
RC       Resource Compiler script file                  Microsoft C/C++,
                                                        Borland C++
RC       Resource Script                                Resource Writer
RC       UUPC configuration files                       UUPC
RC       Windows resource compiler script               RC.EXE -Resource
                                                        WorkShop - OS/2
RCG      Netscape newsgroup file (netsc.rcg)
RCT      Roller Coaster Tycoon
RData    Data file                                      R
RDF      Compiled UIC source code                       Geoworks UI Compiler
RDI      Device-independent bitmap file (RIFF RDIB
         format)
RDP      RDP connection                                 Remote Desktop
                                                        connection
RDX      Datafile                                       Reflex
REC      Archivation protocol                           ARCSERVE
REC      Datafile                                       EpiInfo
REC      Record file                                    Sprint
REC      Windows Recorder Macro File                    WinRecorder
RED      Path info                                      Clarion Modula-2
RED      REDuced nodelist file                          T-Mail nodelist
                                                        Compiler
REF      Cross-reference
REG      OLE Registration file                          Windows 3.x
REG      Registration information or key
REL      Foreground job relocatable file                RT-11
REM      Remarks definition                             Sourcer
REM      Remarks
REP      QWK reader reply file
REP      Report file used by many applications
REP      Report                                         Report Designer -
                                                        CodeReporter - DataBoss
REQ      File request                                   FTN Software
RES      Compiled resource                              Microsoft C/C++,
                                                        Borland C++
RES      DBASE resources                                dBASE IV
RES      Windows compiled resource package              Win
REV      Revision file                                  Geoworks
REX      PharLab executable file (old format)           PharLab
REX      Report definition                              Oracle
REX      Rexx language source file                      Rexx
REZ      Resource file
RF       Sun raster graphics file
RFA      3D BIM Model Family Element                    Autodesk Revit
RFM      Report ForMat (script for customized report)   Nuverb Systems Inc:
                                                        Donarius
RFT      DCA/RFT Revisable Format Text file             IBM DisplayWrite
                                                        4.0-5.1
RGB      SGI RGB image file (RAW)                       SDSC Image Tool
RGX      Symbol tables etc. info                        ReaGeniX code generator
RH       Resource header file                           Borland C++ 4.5
RH       Windows resource file header                   RC.EXE
RHistory Command history logfile                        R
RI       Data                                           Lotus 1-2-3
RIB      Graphics (Renderman Interface Bytestream)      3D Reality
RIC      Fax                                            Ricoh
RIF      RIFF bitmap graphics (Resource Interchange     Fractal Design Painter
         File Format)
RIN      Sound recording participants and information   Soundways RIN-M
         (Recording Information Notification)
RIP      TeleGrafix Remote Imaging Protocol             Maximus 3.0
RIX      Graphics (ColoRIX Image File)                  ColoRIX
RL4      Bitmap graphics
RL8      Bitmap graphics
RLA      Wavefront raster image file                    SDSC Image Tool
RLB      Data hgw.rlb                                   Harvard Graphics Win
RLC      Graphics 1bit/pixel scanner output
RLD      Norton Commander 5.0 temp file                 NC 5.0
RLD      OSIMapDef. RecLoad Definition
RLE      Utah Run Length Encoded rasterfile graphic     SDSC Image Tool
         file
RLZ      REALIZER source code file                      CA-Realizer
RM       RealMedia                                      RealPlayer
RMB      data                                           RegistryMaster
RMI      Windows alternate synthesized sound format     RIFF RMID format
RMK      Make file                                      CA Clipper - RMAKE
RMVB     RealMedia Variable Bitrate                     RealPlayer
RN       XPL program for Nota Bene users
RN4      Random Numeration 4 Encryption Program File
RNA      Real Native Application File
RND      Rendering Slide                                AutoCAD AutoShade
Rnn      Multi volume RAR archive                       RAR
RNO      Runoff file                                    VAX
ROL      FM music Adlib Music File                      Roland
ROM      Read Only Memory image in emulators, AONs,
         etc.
ROO      CODASYL DBMS Database Root                     Oracle
RPB      Data report file used by CP Backup             CP Backup
RPC      Rich Photorealistic Content                    ArchVision
RPD      Database                                       RapidFile
RPF      AutoCAD pattern                                ACAD
RPL      Text document                                  Replica
RPM      Red Hat Package Manager                        Red Hat Linux
RPT      Report file used by many applications
RRD      Reduced Resolution Dataset                     ESRI (GIS)
RS       Data file                                      Amiga Resource -
                                                        Reassembler
RS       Rust language source
RS_      Resource fork of a Macintosh file              Mac-ette
RSC      Resource file                                  ViewMax - many
RSDF     RSD Link Container                             JDownloader
RSL      Application - Project                          resolver one
RSL      Resource Library used by PC Tools for Windows  PC Tools - Win
RSP      Response file (text file containing input
         expected by e.g. LINK)
RSP      Response File                                  OS/2
RST      reStructuredText                               Docutils
RSY      FLEXIT Multishot Survey Raw Data file          FLEXIT
RTF      Rich Text Format text file (help file script)  many - Microsoft Word
RTFD     RTF-Packet                                     NeXT
RTL      HP RTL graphic file
RTL      Run-Time library                               Norton Utilities
RTL      Text file
RTP      RTPatch software update package data file      Pocket soft patch
RTS      Realizer executable file
RTS      Runtime library file                           CA-Realizer
RUL      Echo-conference rules
RUN      AMPL script file                               AMPL
RUN      Makeself shell self-extracting archive         shell
RUN      PC Tools for Windows batch file                PC Tools
RUNZ     pseudo-executable file, used in Portable Apps  RUNZ Framework
         and software installers for Super OS
RUS      Russian text
RV       Mobile pricelist data file                     Mobile
RVF                                                     TRichView
RVW      Review
RVT      3D BIM Model file                              Autodesk Revit
RV       Raw Wind Data
RWS      Borland Resource Workshop symbol file          Resource Workshop
RWS      Resource Workshop data file                    Borland C++
RWX      Criterion RenderWare
RWX      MEME Shape File
RWX      Script                                         RenderWare
RWZ      Microsoft Outlook Rules Wizard File            Microsoft Outlook
RXD      Reflex 1 datafile                              Reflex 1
RZK      File Crypt password file                       All text editors
RZX      File Crypt encrypted file                      File Crypt (Akte
                                                        Krypta, Kriptirnik)

S$$        Temporary sort file                  Sprint
S          ASSEMBLY source code file            unix
S          Multi Edit macro file source         Multi Edit
S          MSTS Shape file                      MSTS
S19        Motorola ASCII format of executables
S1K        S1000 Simnet Format
S3I        Digiplayer/ST3 Sample File           Digiplayer - ST3
S3M        Music (16 channels)                  Scream Tracker 3.0 - DMP
S7I        Seed7 library / include file         Seed7 interpreter and compiler
SA?        Packed mail                          FTN software
SAB        Saber file                           Star Wars: Jedi Knight Jedi
                                                Academy
SAF        see SAIF
SAFE       SafeIT Encrypted
SAIF       Spatial Archive Interchange Format
SAL        Datafile                             SORITEC
SAN        LucasArts' SMUSH/INSANE animation
SAM        Ami Pro data file                    Ami Pro
SAM        Text file                            Samna - Lotus Ami/Ami Pro
SAP        Atari SAP music format
SAR        Archive                              SAR
SAS        SAS Program File                     SAS System
SAT        ACIS ACIS .sat
SATS       Static source                        ATS
SAV        Backup file (saved file)
SAV        Configuration
SAV        Executable                           RT-11
SAV        SPSS "System File"                   PSPP
SAV        Saved game state                     Spider Solitaire (Windows)
SAVER      Screensaver                          Mac OS X
SB         Audio file (signed byte)
SB         Raw Signed Byte (8bit) data          AWAVE
SB         Raw Signed PCM Byte 8bit data        AWAVE
SB         Scratch project                      Scratch
SB2        Scratch 2.0 project                  Scratch
SBD        Storyboard                           Storyboard Editor
SBH        Header                               ScriptBasic
SBI        Sound Blaster Instrument file
           (Creative Labs)
SBK        Emu SoundFont Bank (AWE32 Bank)      Convert (c) Villena
SBL        Stony Brook Pascal library           SB Pascal
SBP        DML program                          Superbase 4
SBR        Support file                         Source Browser
SBT        Notes related to record              Suberbase 4 Windows
SBX        For experimental extensions to       Used by scratchX (scratchx.org)
           Scratch
SBX        Sequenced Box container              Used by SeqBox
SC         Display driver                       Framework II
SC         PAL script                           Paradox
SC         Script                               Borland Paradox
SC3        Renamed dBASE III screen mask file   dBASE IV
SC3        Screen device driver                 Harvard Graphics 3.0
SC3        Saved City                           SimCity 3000
SC4        Saved City                           SimCity 4
SC4        Game Scenario                        RollerCoaster Tycoon Deluxe/
                                                Expansion Pack
SC6        Game Scenario                        RollerCoaster Tycoon 2
SCA        Datafile                             SCA
SCALA      Scala source code file               Scala (programming language)
SCC        Text file
           SCODOL film recorder (Scan
SCD        Conversion Object Description        SCODOL
           Language)
SCF        Standard Chromatogram Format         DNA Baser Assembler
SCF        Standard Chromatogram Format         Staden package
SCF        ?                                    SimAnt or SimTown ??
SCF        Windows Explorer Command (e.g.: show Windows Explorer
           desktop.scf)
SCF        Multimedia show                      ScoreMaker
SCF        Spelling checker configuration file  Symphony
SCH        Project schedule                     Schedule Publisher
SCH        EAGLE schematic file                 EAGLE (program)EAGLE
SCH        Circuit Design Schematic             P-CAD - Orcad - Protel
SchDoc     Circuit Design Schematic             Protel - Altium Designer
SCHEMATIC  MCEdit Schematic file                MCEdit Tool for Minecraft
SCI        Fax                                  SciFax
SCI        System Configuration Information
SCM        Scheme source code file
SCM        Schematic file (Circuit Diagram for  Zuken CadStar
           PCB design)
SCM        StarCraft mission
SCN        SCeNe RTrace
SCN        Screen file                          Kermit
SCO        High score
SCP        Script                               BITCOM
SCPT       Script                               macOS
SCPTD      Script bundle                        macOS
SCR        Any other screen system
SCR        DEBUG source code file               DOS Debug
SCR        Forth screen (source) file           Forth
SCR        Screen - screen snapshot             dBASE IV - Procomm Plus
SCR        Screen font                          LocoScript
SCR        Screen saver                         Windows 3.x
SCR        Screen snapshop
SCR        Script file source                   TeleMate - Kermit - 1st Reader
SCRIPT     Script
SCT        Additional (FPT) screen description  FoxPro
           file
           Raster graphics format used by some
SCTOR      very obscure custom operating
           systems
SCX        Chart                                Stanford Chart
SCX        Graphics format                      ColoRIX
SCX        Main (DBF) screen description file   FoxPro
SCX        StarCraft: Brood War scenario        StarCraft: Brood War
SCY        Security file                        ReaGeniX
SD         Sound Designer I audio file          AWAVE
SD7        Seed7 source file                    Seed7 interpreter and compiler
SDA        Fidonet's Software Distribution
           Network file archive description
SDC        Video                                DigimaxMaster - Samsung NV3
SDC        Synopsys Design Constraints          Electronic Design Automation
                                                Tools
SDF        Microsoft SQL Server Compact Edition
           database file
SDF        Flight data                          microdrones GmbH
SDF        Source definition file               Sourcer
SDF        System Data Format file (fixed
           length ASCII text)
SDI        Software Distribution Network Info
           file
SDK        Roland S-550/S-50/W-30 Disk Image
SDL        Alias Wavefront Scene Description
           Language
SDML       Spatial Data Modeling Language
SDN        Software Distribution Network        pak251.exe
           compressed file archive
SDR        SmartDraw File                       SmartDraw Pro
SDS        MIDI Sample DUMP Standard File
           Self Defining Structure provides for geographic information systems
SDS        N-dimensional very large datasets    and relational database
           using HHCode                         management systems
SDTS       Spatial Data Transfer Standard
SDW        Ami Draw Symbol File
SDX        Sample DUMP Exchange File
SEA        Self-Extracting compressed Macintosh
           file Archive
SEARCH     ACDSee saved search                  ACDSee
SEC        compressed file
SEC        Diskreet encrypted file              Diskreet
SEC        Secret key ring file                 Pretty Good Privacy RSA System
SEC        Secured animation file               Disney Animation Studio
SED        Self extraction directive file       IExpress
SEN        Scifer Archive Format (Internal
           Header Mode)
SEP        Printer separator page
SEQ        ABI Text Sequence                    Applied Biosystems
SEQ        Atari animation file
SEQ        Video                                Tiertex video sequence
SEQ        Sequential Instruction File          Bubble Chamber
SES        Session info                         Clarion Modula-2
SES        Multitrack Audio Session info        Adobe Audition
SET        Configuration file                   1st Reader
SET        Driver sets created by Install       Symphony
SET        Extension used by Norton Backup and  Norton Backup - CPS Backup
           CPS Backup for setup info
SET        Hump Assignments File                FYM
SET        Setup options file
SET        YVD card set file                    YVD
SF         IRCAM Sound File                     CSound package - MixView sound
                                                sample editor
SF         JAR Digital Signature
SF         WPS attribute storage (OS/2          OS/2 WorkPlace Shell
           WorkPlace Shell) wp_root.sf
SF2        Emu SoundFont Bank v2.0 file         AWAVE, Viena, Polyphone, Swami
SFB        Configuration file                   emacs
SFB        HP Soft font (obsolete under
           Windows)
SFD        SoundStage Data file                 AWAVE
SFF        Standard Flowgram Format             DNA Baser SFF Workbench tool
SFF        Scene File Format
SFI        Graphics                             SIS Framegrabber
SFI        Printer font (HP LaserJet landscape) Ventura Publisher
SFL        PCL 4 bitmap font (landscape)        landscape - Intellifont -
                                                Ventura Publisher
SFL        Sound file                           Sound Forge and ACID Pro
SFN        Font                                 SPX
SFO        Bitstream font file - fontware
           format
SFP        PCL 4 bitmap font                    portrait - Intellifont -
                                                Ventura Publisher
SFR        Sonic Foundry Sample Resource        AWAVE
SFS        PCL 5 scalable font file             Intellifont
SFT        Screen font                          ChiWriter
SFV        Simple file verification checksum    many file verification tools
           file
SFX        Renamed dBASE III screen mask file   dBASE IV
SFX        SFX (self-extracting archives)       RAR
           script
SG1        Graphics                             Stanford Graphics
SGF        Document with graphics               Starwriter
SGF        Smart Game Format                    Many board games
SGI        Graphics file                        IRIS - Silicon Graphics
SGP        Statistics                           STATGRAPHICS Plus
SGT        Save/get keyboard macro              Signature
SH         ASCII archive                        SHAR
SH         Unix shell script                    Unix shell interpreter
SH3        Presentation                         Harvard Graphics 3.0
SH3D       Sweet home 3d file                   Sweet home 3d, archivers with
                                                ZIP support
SHA1       SHA1 Checksum verification File      HashCheck (Windows)
SHAR       Shell self-extracting archive        UNSHAR (Unix)
SHB        Background                           CorelShow
                                                Microsoft's shed.exe, JGsoft's
SHG        Segmented Hyper Graphics             Hotspot Builder, EC Software's
                                                Help and Manual
SHK        Apple II archive                     SHRINKIT
SHM        Shell macro                          WordPerfect Library
           Shape file and sdiv id="PYI">        AutoCAD
           PYIource file for text fonts
SHP                                             ArcGIS
           ESRI shapefile

SHR        see SHAR
SHS        Shell Scrap Object File              Windows XP and earlier versions
SHT        HTML format for WWW                  NetScape
SHW        Presentation                         Harvard Graphics 2.0 -
                                                CorelShow
SHW        Slide show                           WordPerfect Presentations,
                                                PMview Slide Show
           Shape entities                       AutoCAD
SHX
           ESRI shapefile                       ArcGIS

SIB        Sibelius file                        Sibelius 1-5
SID        Sound Interface Device file format   SIDplayer, SIDplay, sidplay2 /w
SIF        Setup Installation Files info        Windows NT Setup
SIG        Current program settings             Signature
SIG        Signature file                       gpg, PopMail, ThunderByte
                                                AntiVirus
SIK        Backup file (Sicherungskopie)        Microsoft Word
SIM        Simon document file - Simon
           instruction software editor
SIS        symbian file
SIT        Archive (Macintosh)                  STUFFIT
SK         Skin file
SKI        Skin file                            ?
SKIN       Skin file
SKN        Skin file
SKP        Google SketchUp file
SKY        SYLK Spreadsheet file (used by
           Multiplan)
SL         S-Lang source code file
SLB        P-CAD library (symbols)              P-CAD
SLB        Slide library                        AutoCAD
SLC        SALT (script from Telix) compiled    Telix
           code
SLD        Slide                                AutoCAD
SLDPRT     Part                                 SolidWorks
SLDASM     Assembly                             SolidWorks
SLDDRW     Drawing                              SolidWorks
SLI        Slide                                MAGICorp Slide Service
SLK        Microsoft Excel import format        Microsoft Excel
SLK        SYLK Symbolic Link format data file  MultiPlan
SLL        Sound data file
SLL        Static Link Library                  PowerBASIC
SLN        Microsoft Visual Studio Solution     Microsoft Visual Studio
SLP        SLP command file created by SRCCOM   RT-11
SLP        Localization project file            Sisulizer
SLP        Age of Empires graphics file         Age of Empires (video game)
SLS        Slim source code                     Slim (programming language)
SLT        SALT Script Application Language for Telix
           Telix script source
SLV        Solution for any game                many
SM         Maillist                             SoftSpoken Mailer
SM         Script                               ScriptMaker
SM         SMALLTALK source code file
SM         Text file                            Samna Word
SM         StepMania Step File                  StepMania
SMC        Super MagiCom SNES ROM image         Super MagiCom
SMCLVL     Secret Maryo Chronicles Level        Secret Maryo Chronicles
SMF        Fax                                  SMARTFAX
SMF        3D World Studio mesh files
SMK        Smacker video Format (RAD Video)
SML        System Macro Library                 RT-11
SMM        Ami Pro Macro File                   Ami Pro
SMN        Font (ParaGraph's WorkScript format)
SMP        Sample (sound file)
SMP        Samplevision File                    Samplevision
SMPL       Data                                 Megahedron 3D object
SMS        MSTS Sound management system file    MSTS
SMT        Text file                            Smart Ware II
SN         Compressed song file                 Sound Club editor
SND        Digitized sound file                 Macintosh/ATARI/PC
SND        Power Chords drum sound file         Power Chord
SNDB       SQLNotes database                    SQLNotes
SNG        Song (midi sound)                    Midisoft Studio - Prism
SNG        Saved game file for StarCraft        StarCraft
SNO        SNOBOL4 source code file
SNP        Book-shelf for .BOO                  READIBM
SNP        Microsoft Access report snapshot
SNP        Output video format from Computer
           Eyes equipment
SNX        Saved game file for StarCraft: Brood StarCraft: Brood War
           War
SO         shared object, dynamically linked    Unix, Linux
           library
SOAR       Soar Production file
SOF        Altera FPGA programming file         Altera Quartus
           (internal RAM)
SOL        Solution e.g. game walkthroughs
           Adobe Flash shared object ("Flash
SOL        cookie") (Movie, film, video and     Adobe Flash
           multimedia file type)
SOL        Solidity source code
SOM        Network serial numbers               Quattro Pro
SOM        Sort information                     Paradox
SON        Song                                 SBStudio II
SOU        Temporary BATCH file                 RT-11
SOU        SBStudio II Sound File               SBStudio II
SOU        Sound data (sound tool)
SP         Archive (unix)                       SPLINT
SPC        Program                              Microsoft Multiplan
SPC        Temporary file                       WordPerfect for Win
SPC        SNES SPC-700 Sound File              SNES games
SPC        Spectroscopic data (scientific)      Thermo Scientific
SPD        Scalable font                        Speedo - Harvard Graphics 3.0
SPF        Slide presentation file              EnerGraphics
SPF        data                                 SQR Portable Format
SPG        Glossary                             Sprint
SPI        Graphics (Siemens and Philips
           scanner)
SPIFF      Still Picture Interchange File
           Format
SPIN       Spin source file                     Parallax Propeller
                                                Microcontrollers
SPL        Archive                              SPLINT
SPL        Customized printer driver            Sprint
SPL        Divided file segment                 Slice
SPL        Personal spell dictionary            Signature
SPL        Print spooling file                  Windows 3.x
SPL        Sample
SPM        Data wp{wp}.spm                      WordPerfect
SPP        Printer file                         Sprint
SPR        Document letter                      Sprint
SPR        Generated executable screen file     FoxPro
SPR        Sprite
SPR        Story Board sprites
SPS        Exported SyncBack profile            SyncBack
SPS        Screen driver                        Sprint
SPS        SPSSx source code file               VAX/VMS
SPT        Data support file (MITAC disk/system MITAC disk/system management
           management utility pack)             utility pack
SPT        SPITBOL source code file
SPW        Worksheet                            SigmaPlot
SPX        Compiled executable screen file      FoxPro
SPX        Ogg Speex bitstream^[1]              Xiph.Org Foundation
SQD        Squish message base                  Squish
SQI        Squish message base index            Squish
SQL        Squish message base lastread         Squish
           pointers
SQL        Structured Query Language            Any SQL database
SQLite     SQLite                               Firefox SQLiteBrowser
SQM        Windows Live Messenger log file
SQN        Note file                            SquareNote
SQZ        Archive                              SQUEEZE
SQZ        FOXPRO Squeeze file                  FOXPRO
SRC        Source code                          Aurora Compiler
SRC        Multi-edit source                    Multi-Edit
SRC        Source                               DataFlex
SRF        Sun Raster File graphics file
SRP        Script                               QuickLink
SRT        Subtitle format                      SubRip
SS         Bitmap graphics                      Splash
SS         Screen saver                         DN
SSC        Celestia Solar System Catalog file   Celestia
SSC        Stellarium Script                    Stellarium
SSD        Datafile                             SAS/PC
SSF        Graphic file                         SnagIt Studio File/PC
SSFREC     Super Smash Flash 2 replay file      File for Super Smash Flash 2
SSG        Saved game                           Simsig
                                                Media playback devices /
SSIF       Stereoscopic Interleaved file        software that supports Blu-ray
                                                3D
SSO        SmartSong                            SertintyONE
SSP        Datafile                             SAS Transport
SSR        FLEXIT Singleshot Survey Raw Data    FLEXIT
           file
SST        AVHRR graphic file
SSV        Spreadsheet viewer file
ST         Instrument library                   Scream Tracker
ST         SMALLTALK source code file           Little Smalltalk
ST         Stamp                                NeoPaint
STA        Data file                            Statistica
STA        Saved state                          Reflection 4.0
STA        Stack                                Spinmaker Plus
STB        Symbol table file                    RT-11
STB        Stub library                         Genus GX Kernel
STC        Celestia Star Catalog file           Celestia
STC        OpenOffice.org XML spreadsheet       OpenOffice.org Calc
           template
STD        State Transition Diagram graphic     Prosa
           file
STD        OpenOffice.org XML drawing template  OpenOffice.org Draw
STEAMSTART STEAMSTART file                      Steam (software)
STEP       Standard for the Exchange of Product universal format for CAD
           Data                                 exchange
STF        Archive                              SHRINKTOFIT
STF        Setup Table File
STI        OpenOffice.org XML presentation      OpenOffice.org Impress
           template
STK        eBook                                Starebook
STL        Stereolithography Interface Format
STL        Subtitle files EBU-standard
STM        Music format (4 channels) (Scream    ST - DMP
           Tracker Module)
STM        State Transition Diagram model file  Prosa
STO        Pascal stub OBJ file                 Genus GX Kernel
STP        Subtitler Project                    Belle Nuit Subtitler
STP        Standard for the Exchange of Product universal format for CAD
           Data                                 exchange
STR        Gate3 table structure file
STR        Structure list object file           dBASE Application Generator
STR        PlayStation video file
STRINGS    Strings file                         Apple
STS        Music format (Scream Tracker Song)   ST 2.0-2.3
STS        Project status info                  Microsoft C/C++
STU        Studio Project                       Pinnacle Studio (video editing
                                                software)
STUFF      EVE Online compressed file archive   CCP hf
STW        Data file                            SmartTerm for Windows
STW        OpenOffice.org XML text document     OpenOffice.org Writer
           template
STX        Electronic book                      SmarText
STX        Music format
STX        Tax form                             CA-Simply Tax
STY        Ami Pro Template (Style); used by    Ami Pro
           other programs for `styles`
STY        Style library or sheet               many
SU         Saurus source file
SU?        Packed mail                          FTN software
SUB        Subtitle format                      SubViewer; Author David
                                                Dolinski
SUC        Saurus byte-code file                Saurus VM
SUF        Sony camera configuration file       XDCAM-EX camcorders
           (setup.suf)
SUI        SUIT library                         Simple User Interface Toolkit
SUM        Summary
SUN        Sun rasterfile graphics file         Sun Microsystems
SUO        Solution User Options                Microsoft Visual Studio
SUP        Subtitle file (Blu-ray encapsulated  SupRip
           container)
SUP        Supplementary dictionary             WordPerfect for Win
SUR        Surface topography (in native "SURF" MountainsMap
           format)
SV4        Saved Game File                      RollerCoaster Tycoon
SV6        Saved Game File                      RollerCoaster Tycoon 2
           Represents the ServiceHost instance  Windows Communication
SVC        hosted by Internet Information       Foundation
           Services
SVD        Autosave file for document           Microsoft Word
SVG        Autosave file for glossary           Microsoft Word
SVG        Scalable Vector Graphics             many
SVQ        MRC-Pro sequencers music format      Roland Corporation synths such
                                                as XP or Fantom series
SVS        Autosave file for style sheet        Microsoft Word
SVW        Super Video Windows                  Conversion Artist
SVX        Interchange, 8SVX/16SV               AWAVE
SVY        FLEXIT Survey data                   FLEXIT
SW         Raw Signed Word (16bit) data         AWAVE
SWF        Shockwave Flash                      Macromedia
SWG        SWIG source code                     SWIG
SWG        SWAG Pascal Snippets file            SWAG
SWIFT      Swift source code                    Swift (programming language)
SWP        Document backup                      Sprint
SWP        Swap file
SWT        Hump Routes File                     FYM
SXC        OpenOffice.org XML spreadsheet       OpenOffice.org Calc
SXD        OpenOffice.org XML drawing           OpenOffice.org Draw
SXG        OpenOffice.org XML master document
SXI        OpenOffice.org XML presentation      OpenOffice.org Impress
SXM        OpenOffice.org XML formula           OpenOffice.org Calc
SXP        3DS Process file                     3D Studio
SXW        OpenOffice.org XML text document     OpenOffice.org Writer
SY1        SmartPix symbol library              Ami Pro
SY3        Harvard Graphics format
SY3        Symbol file                          Harvard Graphics 3.0
SYD        Backup of startup files created by
           QEMM (?) autoexec.syd
SYD        Sysedit backup file                  Sysedit
SYG        Monitor and handler files created by RT-11
           SYSGEN
SYM        Compiler symbolic information file
SYM        P-CAD component (symbols)            P-CAD
SYM        Precompiled headers                  Borland C++
SYM        Program symbol table                 Power C, Microsoft ILink
                                                incremental linker
SYM        Symbol file                          Harvard Graphics 2.0, Microsoft
                                                Windows SDK
SYN        SDSC Synu image file                 SDSC Image Tool
SYN        Synonym file                         Microsoft Word 5
SYS        Datafile                             SYGRAPH - SYSTAT - SPSS/PC
SYS        System file - device driver or       DOS
           hardware configuration info
SYW        Graphics file (symbol)               Harvard Graphics Win
SYW        Yamaha SY-85/SY-99 Wave File         Convert (c) Villena
SZPROJ     SZInstallSystem Project              SoftwareZator 2011 Standart
                                                Edition

T         Archive without            tar
          compression (tape)
T         TADS source
T         Tester symbol table        ReaGeniX code generator
T?H       Turbo Help file (Pascal,   Borland Thelp
          C, Assembler, ...)
T$M       AVG scan log files^[2]     AVG
T2B       Bookeen Cybook thumbnail   Cybook
t2flow    Taverna 2 workflow         Taverna workbench
          definition
T2L       True2Life file format      3D Internet content developers
T44       Temporary file for Sort or dBASE IV
          Index
T64       Program                    C64S emulator
TAG       Query tag name             DataFlex
TAH       Help file for Turbo        Borland C++
          Assembler
TAK       Audio codec, Lossless      Winamp (+Plugin), foobar2000 (+Plugin),
          audio file format          Media Player Classic - BE
TAL       Adobe Type Align           Adobe
TAL       Text illustration          TypeAlign
TAP       Tape file                  ZX Spectrum emulator by g.a.lunter
TAR       Archive                    TAR
TAZ       Archive                    WinZipNT - TAR - COMPRESS
TB        Tab file (Virtual Desktop  Tabbery
          Tab)
TB1       Font file                  Borland Turbo C
TB2       Font file                  Borland Turbo C
TBF       Fax                        Imavox TurboFax
TBK       FOXPRO template backup     FOXPRO
          file
TBK       Memo backup                dBASE IV - FoxPro
TBK       Toolbook                   Asymetrix ToolBook
TBL       Short for Table            used by many programs
TBL       Aldus TableEditor file     TableEditor
TBL       binary Unicode conversion  Volkov Commander, DOSLFN
          table
TBL       Gate3 table file
TBL       Graphics file (native      PageMaker TableEditor
          format)
TBL       Table of values            OS/2
TBR       Norton Desktop custom      NDW
          toolbar
TBS       Text elements ??           Microsoft Word
          (Textbausteine)
TBX       Table                      Project Scheduler 4 - TermBase eXchange
                                     (ISO 30042)
TBZ       Archive                    WinZipNT - TAR - Bzip2
TC        Configuration              Turbo C - Borland C++
TCC       TI-Nspire OS upgrade file  TI-Nspire CX CAS
TCH       Help file                  Turbo C - Borland C++
TCL       Tool Command Language      Tcl
          source code
TCO       TI-Nspire OS upgrade file  TI-Nspire CX
TCT       Drawing Template           TurboCAD for Windows
TCW       Native Drawing File        TurboCAD for Windows
TD        Config from Turbo Debugger Turbo Debugger
TD0       Compressed disk image file Teledisk
TD1       Multi-part disk image file Teledisk
TD2       Configuration file         Turbo Debugger for Win32
TDB       Database                   TACT
TDDD      Imagine Object File Format Imagine
TDF       Speedo font file
TDF       Typeface definition file   Speedo
TDH       Help file for Turbo        Borland C++
          Debugger
TDK       Keystroke recording file   Turbo Debugger
TDR       Contens of Arvid tape
TDS       Symbol table               Turbo Debugger
TDT       Thumbnail data             AVCHD
TDW       Configuration file         Turbo Debugger for Windows
TEC       Data                       TECPLOT output
TEC       TECO macro file            TECO
          ("compiled" form)
TEF       Fax                        Relisys TEFAX
TEL       Host file                  Telnet
TEM       Input template             IconAuthor
TEM       Turbo Editor Macro         Borland C++
          Language script
TERM      Terminal File
TES       TECO macro file (source    TECO
          form)
TET       Tetris results             DN
TEX       Datasheet                  Idealist
TEX       TeX text file              Scientific Word - TeX
TEX       Image                      Slimtex
TEXT      Text file
TF        Configuration              Turbo Profiler
TFA       Area file                  Turbo Profiler
TFC       Catalogue file             Tobi's Floppy Cataloguer
TFF       self executing TansForm    TansForm
          dialogue
TFH       Help file for Turbo        Borland C++
          Profiler
TFM       Tagged font metric file    Intellifont
TFM       TeX font metric file       TeX
TFS       Statistical information    Turbo Profiler
TG1       Project file               On Target
TGA       Targa bitmap               Paint.NET, many raster graphics editors
TGZ       Archive                    WinZipNT - TAR - GNUzip
TH?       Packed mail                FTN software
THE       Windows'95 Desktop Theme   Microsoft Plus
THEME     Windows Theme              Microsoft Windows 95 with Plus!, 98 and
                                     later
THEMEPACK Windows Theme package      Microsoft Windows 7 and later, many file
                                     archivers with CAB support
                                     Picture Publisher, PhotoMagic, Canon
                                     Digital Cameras, and Sony Digital Cameras
THM       Thumbnail or Theme File    create these Thumbnail files; also used
                                     for Sony Ericsson Theme File, for a cell
                                     phone
THP       Nintendo proprietary video Various Nintendo games
          format
THR       ThredWorks Embroidery      Thred, Embroidermodder
          Format
THS       Thesaurus dictionary       WordPerfect for Win
TIB       Acronis True Image Backup  Acronis True Image
          FTN special file with
TIC       assotiated file            ALLFIX
          description
TIF       see TIFF
TIFF      TIFF (tagged image format  Alchemy - PhotoStyler -PageMaker -
          file) bitmapped file       CorelDRAW
TIGER     Tomb Raider binaries files Ubi
TIL       Fuzzy logic knowledge base Togai InfraLogic Fuzzy-C Compiler
TIP       Digital Signage            Tru-Designer, Tru-Player, Tru-Scheduler
          Presentation               part of Tru-i Suite^[3]
TIS       Tile set                   MahJongg 3.0
TJL       Backup file                VAXTPU editor
TLB       Reference table            Bubble Chamber
TLB       Text library               VAX
                                     A binary file with information about a COM
                                     or DCOM object so other applications can
TLB       Type library [1]           use it at runtime. Created by Visual C++
                                     or Visual Studio. Used by many Windows
                                     applications.
TLC       Compiled Tool Command      Swat
          Language source code
TLD       Disk Image                 Teledisk
TLG       Transaction Log            Intuit QuickBooks
TLH       Typelib Generated C/C++    Visual C++
          Header
TLP       Project                    TimeLine
TLX       Website builder            Trellix
TM2       Typical Meteorological     Typical Meteorological Year
          Year data (new)
TMC       TI-Nspire OS upgrade file  TI-Nspire CM-C CAS
TMF       Tagged Font Metric file    WordPerfect for Win
TMF       TiVo movie                 TiVo
TMO       ZTG global optimizer       Zortech C++
          default output file
TMO       HandsHigh ThoughtManager   ThoughtManager Desktop
          Outline
TMO       TI-Nspire OS upgrade file  TI-Nspire CM-C
TMP       Temporary file             (Several programs)
TMPL      Template
TMS       TeleMate compiled script   TeleMate
TMY       Typical Meteorological     Typical Meteorological Year
          Year data (old)
TMY2      Typical Meteorological     Typical Meteorological Year
          Year data (new)
TNC       TI-Nspire OS upgrade file  TI-Nspire CAS
TNO       TI-Nspire OS upgrade file  TI-Nspire
TNS       TI-Nspire document         TI-Nspire series
TOC       Table Of Contents text
          file (ASCII)
TOCG      TorgaNET Diplomatic Cables State Department of Torga
TOK       Borland C++ 4.x reserved   BCW.EXE
          word list
TOG       TorgaNET                   TorgaNET database file
          TopicCrunch SEO Project
TOPC      file holding keywords,
          domain and search engine
          settings (ASCII)
TORRENT   TORRENT File               BitTorrent clients (various)
TOS       Character file             The Only Sheet
TOS       Self-extracting file
          archive (Atari ST)
TP        Session-state file         Turbo Profiler
TP        Turbo Pascal cfg file      Turbo Pascal
                                     TinkerPlots and Fathom Dynamic Data
TP        TinkerPlots Document       Software; documents contain data tables,
                                     graphs, text, pictures, etc.
TP3       Template                   Harvard Graphics 3.0
TPB       Downloadable PCL Soft font HiJaak
          file backup
          File produced when an
TPC       inter-Topicscape topic     3D Topicscape
          link file is exported to
          Windows
TPF       Downloadable PCL Soft font HiJaak
          file
TPF       Print data in EMF format   ThinPrint
TPH       Help file                  Turbo Pascal
TPL       Resident units library     Turbo Pascal
TPL       Template file              GoldEd -ITrack
TPL       Template                   Harvard Graphics 2.0
TPOLY     Data                       TPOLY 3D object
TPP       Protected Mode Units       Borland Pascal 7.0
TPT       Digital Signage            Tru-Designer, Tru-Scheduler part of Tru-i
          Presentation Template      Suite^[3]
TPU       Borland Pascal DOS Mode    Borland Pascal
          Library
TPU       Command file (VAXTPU       VAXTPU editor
          editor)
TPW       Borland Pascal Windows     Borland Pascal
          Library
TPW       Session-state file         Turbo Profiler for Windows
TPZ       Archive                    TAR - GNUzip
TR        Man page input suitable    cawf2.zip
          for troff -man
TR        Session-state settings     Turbo Debugger for DOS
TR2       Session-state settings     Turbo Debugger for Win32
TRC       Debug support file         Power CTrace
TRASH     File found during a file   Windows
          scan as bugged
TRE       Directory tree file        PC-Tools
TRD       Datafile                   TrID file identifier filetypes definitions
                                     package
TRIA      Data                       Greg Hood's ASCII Triangle
TRIB      Data                       Greg Hood's Binary Triangle
TRIF      Tiled Raster Interchange
          Format
          Track (i.e. video
TRK       sequence), used by many
          games
TRM       Terminal settings          Windows 3.x
TRN       Translation support file   Quattro - Clarion
TRP       MPEG-2 Part 1 multiplexed  Digital video broadcast, DVRs, video
          video stream               players
TRS       Executable file            Micrografx or password file
TRS       WiSo Mein Geld 2007
TRS       IBM Mainframe log file     TRSMAIN
TRU       True Basic source file
TRW       Session-state settings     Turbo Debugger for Windows
TRY       Typical Meteorological     TRNSYS
          Year data (variant)
TS        MPEG transport stream      Various media players / software
TS        Qt Linguist TS File        Trolltech Qt Linguist
TS        TypeScript source file
TSE       Data                       Light Map Maker ASCII Scene
TSK       Microsoft Multimedia Task  Win95
          Application
TSL       Exported Schedule          Tru-Scheduler part of Tru-i Suite
TSM       Turbo Assembler Manual     TASM for OS/2
TST       Printer test file          WordPerfect for Win
TST       ExamView papers and online can be opened with WinRAR, ExamView, and
          tests                      TestGen software.^[4]
TSV       Tab Separated Values
TTE       TrueType Font file         Windows EUDC editor
TTF       TrueType Font file
TU?       Packed mail                FTN software
TUD       The Ultimate Draw file     The Ultimate Draw
TUT       Tutorial
TV        Table view settings        Paradox
TVF       Table view settings        dBASE
TVn       Overflow file above insert WordPerfect for Win
          point in Doc n
TWF       Warp Map File              Geo Semiconductor, Inc eWarp Pro
                                     Development Took Kit
TXC       Test Configuration Format
TXF       Tax eXchange Format
TXI       Support file               TeX
TXT       Common name for ASCII text Microsoft Notepad
          file
TXT       Tab-Delimited Text File    Microsoft Excel
TXT       Document Extension         TextEdit
TXW       Yamaha TX-16W Wave File    Convert (c) Villena
TY        TiVo movie                 TiVo
TYM       Time Stamp (PageMaker 4)   PageMaker 4
TZ        Archive                    TAR - COMPRESS
TZB       Archive                    TAR - COMPRESS - BTOA
TZL       Tanzzle pattern file       Tanzzle
TZX       Tanzzle image file         Tanzzle

U3D    Model file format                Ultimate 3D
U3D    Universal 3D                     Adobe Acrobat
U8     Sample
UB     Raw Unsigned Byte (8bit) data    AWAVE
UC2    Archive                          UC II
UCN    New archive                      UC II
UCS    Unknownsoft Service Pack (mainly Unknownsoft Computer Systems
       for Shadow OS 2009)
UDF    Filter                           Aldus Photostyler
UDO    Data                             Moray User Defined Object
UDIWWW bookmark data                    UdiWWW
UDW    Raw Unsigned DWord data          AWAVE
UE2    Encrypted archive                UC II
UFI    data                             UFO CaptureV2 settings -
UFO    graphic file                     Ulead Photo Impact
UHA    UHarc archive
UHS    Universal Hint System (binary
       file)
UI     Espire source code file          Geoworks UI Compiler Geos
UI     Qt Designer's UI File            Trolltech Qt Designer
UI     User interface                   Sprint
UIF    Long prompts for windows         WordPerfect for Win
UIH    Espire header file               Geoworks UI Compiler Geos
UL     ULAW audio file
ULD    Information about uploaded files Procomm Plus - Datastorm Technologies,
                                        Inc.
ULF    data                             MRF Mapping Tool Kit Universal List
                                        Format
ULT    Music                            UltraTracker
UMB    Backup file                      MemMaker
UMP    Umple UML Programming Language   Umple
       Format
UMX    Unreal Music Package             Unreal Tournament
UNF    Universal NES Image Interchange
       File Format
UNI    Datafile                         Forecast Pro
UNI    Music format                     UNIMOD - MIKMOD
UNIF   Universal NES Image Interchange
       File Format
       Text file containing finite      Originally used by SDRC for its I-deas
UNV    elements nodal coordinates and   software; a lot of simulation software
       more See notes                   use it today
UNX    Text file containing UNIX
       specific info
       UniqueObject Markup Language
UOML   (UOML) is a XML-based markup
       language
UOP    Uniform Office Format
       presentation
UOS    Uniform Office Format
       spreadsheet
UOT    Uniform Office Format text
UPD    Update data                      dBASE
UPO    Compiled update data             dBASE
URL    Internet Shortcut (URL)          Windows Explorer
URT    Utah Raster Toolkit
USDZ   Augmented Reality (AR) File      Apple, Pixar
USE    Log file
USP    Printer font with USASCII        Adobe PageMaker
       extended character set
USR    User database file               Procomm Plus - Turbo C++ tour
UST    UTAU vocal track                 UTAU
UT!    datafile                         uTorrent
UTZ    Mobile Phone Theme               Sony Ericsson
UU     Encoded file (ASCII)             UUENCODE/UUDECODE - Uuencoding
UUE    Encoded file (ASCII)             UUENCODE/UUDECODE - Uuencoding
UW     Raw Unsigned Word 16bit data     AWAVE
UWF    UltraTracker WaveSample          UltraTracker
UXP    SmartData Object                 SertintyONE
UZED   Compressed Unicode GEDCOM file   Family Tree Builder

V            Consistency check support file ReaGeniX code generator
V            Main input file for an image   Vivid 2.0
V            Coq source file
V            Verilog source file
V1, V2, ...  Split parts of a whole file    JJSplit
V4P          vvvv patch                     vvvv
V64          Nintendo 64 ROM                Nintendo 64 emulators
V8           Covox 8bit file                AWAVE
V10          Data                           Gouraud Shaded Vectors
                                            Voucher management included in
V2D          Voucher design file            JFire (e.g. when printing a
                                            voucher)
VAI          multimedia                     PhotoDub document
VAL          Validity checks and            Paradox for Windows
             referential integrity
VAL          Values list object file        dBASE Application Generator
VALA         Sourcecode                     Vala
VAN          Animation                      VistaPro
VAP          Value Added Process            NetWare 2.xx
VAP          Dialogic indexed adpcm voice   VBASE/40
             file
VAR          Variable file                  IconAuthor
VB           Visual Basic .Net source file  Visual Basic .NET
VBOX         virtual machine settings file  VirtualBox
             (in XML format)^[5]
VBOX-EXTPACK VirtualBox extension package^  VirtualBox
             [6]
VBOX-PREV    backup of virtual machine      VirtualBox
             settings file
VBPROJ       Visual Basic .Net project file Visual Basic .Net Express and
                                            Visual Studio 2003-2010 Project
VBR          Visual Basic Custom Control    Visual Basic
             file
VBS          VBScript script file           VBScript
VBX          Visual Basic eXtension         Visual Basic
VBZ          Visual Basic Setup Wizard      Setup Wizard
             Template
VC6          Graphite - 2D and 3D drafting  Ashlar-Vellum
VC           Include file with color        Vivid 2.0
             definitions
VC           Spreadsheet                    VisiCalc
VCA          Visual Clip Art
VCD          VideoCD
VCD          VirtualDrive CD Image File
VCD          Value Change Dump (Verilog)
             temporal database file
VCD          VisualCADD Drawing File
VCE          Visual CertExam File           VCE Exam Simulator
VCF          Virtual Contact File
VCLS         VocaListener voice scanner     VocaListener Plug-in (Vocaloid3)
             file
VCR          VCR drivers for Arvid
VCW          Visual workbench information   Microsoft Visual C++
VCX          Spreatsheet                    VisiCalc Advanced
VDA          Targa bitmap graphics          many raster graphics editors
VDI          Virtual Disk Image             VirtualBox
VDO          Story Board video image        Story Board
VDOC         Vector Document File           a Future Corporation Pty. Ltd.
                                            (Australia)
VDR          Drawing                        ComputerEasy Draw
VEG          Vegas Project                  Sony Vegas
VEW          GroupWise for Windows          Win
VEW          View file                      Clipper 5 - Lotus Approach
VF0          Database file                  OTExpert 5
VFA          FontLab Database file          FontLab
VFD          Virtual Floppy Disk            Windows Virtual PC (among others)
VFM          Ventura Font Metrics file
VFM          Voting Form                    Voter
VFN          Voting Form for Customers      Voter
VGA          VGA display driver
VGA          VGA display font
VGD          VGA display driver             Generic CADD
VGM          Video Game Music audio format
VGR          Graphics file                  Ventura Publisher
VHD          VHDL source file
VHD          Virtual Hard Disk              Windows Virtual PC (among others)
VHDX         Virtual Hard Disk v2           Microsoft Hyper-V (among others)
VI           LabVIEW Virtual Instrument     LabVIEW
VI           Graphics file                  Jovian Logic VI
VI           Watcom editor script           VI.EXE
VIA          VIA Document Project           VIA Text Editor
VIC          see VICAR
VICAR        Graphics (Video Image
             Communication and Retrieval)
VID          Bitmap graphics (YUV12C
             M-Motion Frame Buffer)
VID          Graphics format                Word&Deed
VID          MS-DOS Shell Monitor file      MS-DOS 5
VID          Screen device driver           Word
VIF          see VIFF
VIFF         Khoros Visualization Image     SDSC Image Tool
             File Format
VIK          Graphics format (VIKING)
VIM          Vim script file                Vim text editor
VINF         data                           ReMPEG log file - frames info
VIR          Virus or infected file
VIS          VIS graphics file
VLM          Vellum, Vellum 2D, Vellum      Ashlar-Vellum
             Draft, Vellum 3D, DrawingBoard
VLM          Virtual Loadable Module        Netware
VLOGO        Vector Logo File               a Future Corporation Pty. Ltd.
                                            (Australia)
VM           Virtual Memory file            Geoworks
VMC          Virtual memory configuration   DOS/4GW PM 32X DOS Extender
VMCZ         Hyper-V Exported Virtual       Microsoft
             Machine
VMDK         Virtual Disk file              VMware
VMF          Font characteristics           Ventura Publisher
VMG          Nokia message file format      Text Message Editor (Nokia PC Suite
                                            )
VMS          Text file containing VMS
             specific info
VMT          Source Engine resource file    Source Engine
VO           Include file with object       Vivid 2.0
             definition
VOB          Video Object                   DVD-R, DVD-RW
VOC          Sound format (Creative Lab's   PlayVoc
             Sound File)
VOF          Object folder                  VZ Programmer
VOP          Visual Orangator Project
VOP          Visual OTTHYMO Project
VOX          Dialogic adpcm file            AWAVE, CoolEdit
VP           3DS Video posting              3D Studio
VPF          Vector Product Format
VPG          Graphics file                  VPGraphics
VPH          Virtual Pascal Help            VP/OS2
VPI          Virtual Pascal Unit            VP/OS2
VPM          Garmin Voice Processing Module
VPP          Visual Paradigm Project        Visual Paradigm for UML
VQA          Vector Quantized Animation     The Legend of Kyrandia
VQM          Hardware description language  Altera
VRM          Overlay file                   QuattroPro
VRM          Visual rexx source             WATCOM VREXX
VRML         Virtual Reality Modeling       NetScape
             Language
VRP          Project                        WATCOM VX?Rexx
VRS          Video Resource e.g. video      WordPerfect
             device driver
VS           Vellum Solids                  Ashlar-Vellum
VS           Include file with surface      Vivid 2.0
             definition
VSD          Diagram                        Shapeware Visio
VSD          Visio drawing                  Visio
VSDM         Visio macro-enabled drawing    Visio
VSDX         Visio drawing                  Visio
VSM          Visual Simulation Model        VisSim
VSP          Sprite                         SPX
VSQ          Vocal synthesizer track data   Vocaloid2, Vocaloid3
VSQX         Vocal synthesizer track data   Vocaloid3
VSS          SmartShapes file               Shapeware Visio
VSS          Visio Stencil                  Visio
VSSM         Visio Macro-enabled Stencil    Visio
VSSX         Visio Stencil                  Visio
VSSX         Visio Stencil                  Visio
VST          Truevision Vista graphics      many raster graphics editors
VST          Visio Template                 Visio
VSTM         Visio Macro-enabled Template   Visio
VSTO         Microsoft Office add-in file   Microsoft Visual Studio
VSTX         Visio Template                 Visio
VSVNBAK      VisualSVN Server repository    VisualSVN Server
             backup
VTF          Source Engine resource file    Source Engine
VUE          Animation                      3D Studio
VUE          View                           dBASE IV - FoxPro
VVV          Video game save                VVVVVV
VW           Text file                      VolksWriter
VWR          File viewer file               PC Tools
VWX          CAD File                       VectorWorks 2008
VXD          Windows 3.x virtual device     Windows 3.x
             driver
VZT          Temporal database file         GTKWave data file

W         Word chart file                                 APPLAUSE
W01       Yamaha SY-series wave files                     AWAVE
W01       Yamaha TX16W wave file                          AWAVE
W30       Printer font                                    AST TurboLaser -
                                                          Ventura Publisher
W31       Startup file                                    Windows 3.1
W3A       Warcraft III Abilities Export File              Contained in a
                                                          Warcraft III map
W3B       Warcraft III Destructables Export File          Contained in a
                                                          Warcraft III map
W3D       Warcraft III Doodads Export File                Contained in a
                                                          Warcraft III map
W3D       Westwood 3D object format                       3D models used in
                                                          Renegade and Generals
W3D       Shockwave 3D object format
W3G       Warcraft III Replay File                        File for Warcraft III
W3H       Warcraft III Buffs Export File                  Contained in a
                                                          Warcraft III map
W3M       Warcraft III Map                                File for Warcraft
                                                          III: Reign of Chaos
                                                          File for Warcraft
W3N       Warcraft III Campaign                           III: The Frozen
                                                          Throne
W3O       Warcraft III Object Data Export File            Contained in a
                                                          Warcraft III map
W3P       Warcraft III Save                               Save File for
                                                          Warcraft III
W3Q       Warcraft III Upgrades Export File               Contained in a
                                                          Warcraft III map
W3T       Warcraft III Item Export File                   Contained in a
                                                          Warcraft III map
W3U       Warcraft III Unit Export File                   Contained in a
                                                          Warcraft III map
W3V       Warcraft III Save                               Save File for
                                                          Warcraft III
                                                          File for Warcraft
W3X       Warcraft III Expansion Map                      III: The Frozen
                                                          Throne
W3Z       Warcraft III Save                               Save File for
                                                          Warcraft III
          renamed system files (AUTOEXEC.BAT, COMMAND.COM Windows 95, 98, ME
W40       , CONFIG.SYS,DBLSPACE.BIN.DRVSPACE.BIN,         (dual-boot feature)
          MSDOS.SYS) of Windows version
W44       Temporary file for Sort or Index                dBASE
W95       Something for Windows95                         Win95
WAD       Where's All the Data?                           Doom - Doom2
WAD       Nintendo proprietary format for Wii channels,   Nintendo Wii
          menus, etc.
WAG       Yard Contents File                              FYM
WAI       Warcraft III AI Data File                       Warcraft III AI Data
                                                          File
                                                          A Java file format
WAR       Java Web Archive                                used to package and
                                                          deploy web
                                                          applications
WAS       ProComm Script File (source code)               ProComm
WAV       Sound format (Microsoft Windows RIFF WAVE)      Media Player
WAX       TVTonic WAX video packaging                     Wavexpress TVTonic
WAX       ProComm compiled script                         ProComm
                                                          Windows Media Player 
WAX       Windows Media Audio Shortcut                    (Windows Media Audio
                                                          Redirector)^[7]
WB1       Notebook                                        Quattro Pro
WB2       Spreadsheet                                     Quattro Pro
WBF       Microsoft Windows Batch File                    Catch
WBK       Document/workbook or Microsoft Word backup file WordPerfect for Win
                                                          or Microsoft Word
WBT       Norton Desktop                                  Norton Desktop
WBT       Wilsonware Batch file                           Winbatch
WCD       Condes Event Data file                          Condes
WCD       Macro token list                                WordPerfect for Win
WCH       WordPerfect Macro Facility                      WP
WCM       Data transmission file                          Microsoft Works
WCM       Macro                                           WordPerfect for Win
WCP       Product information description                 WordPerfect for Win
WD        InfoSelect Data file
WDB       Database                                        Microsoft Works
WDB       World Database                                  Lego Island
WDM       Admin tool connection definition                War FTP
WE?       Packed mail                                     FTN software
WEB       WEB source code file                            Web Easy Professional
WEBLOC    Web internet location                           macOS
WebOOGL   Web Object Oriented Graphics Library
WFB       Turtle Beach WaveFront Bank                     AWAVE
WFD       Turtle Beach WaveFront Drum                     AWAVE
WFM       Form object                                     dBASE Form Designer
WFN       Font                                            CorelDRAW
WFP       Turtle Beach WaveFront Prog.                    AWAVE
WFT       Web Family Tree                                 GRAMPS
WFX       Data file                                       Winfax
WG1       Worksheet                                       Lotus 1-2-3/G
WG2       Worksheet                                       Lotus 1-2-3 for OS/2
WID       Width table                                     Ventura Publisher
WIFI      Torga OS Wifi Settings Database                 14th Information
                                                          Division (Torga)
WIKI      Wiki markup (various flavors)                   Wikis
WIM       Windows Imaging Format                          ImageX
WIN       Window file                                     FoxPro - dBASE
WIREFRAME Data                                            EMSE mesh
WIX       Windows Installer XML                           WiX
WIZ       Page wizard                                     Microsoft Publisher
                                                          Lotus 1-2-3 version
WK1       Spreadsheet                                     2.x - Lotus Symphony
                                                          1.1+
WK3       Spreadsheet                                     Lotus 1-2-3 version
                                                          3.x
WK4       Spreadsheet                                     Lotus 1-2-3 version
                                                          3.4
WKB       Document                                        WordPerfect for Win
WKE       Spreadsheet                                     Lotus 1-2-3
                                                          educational version
WKF       VISI Working file                               Vero Software
WKI       Spreadsheet format                              Lotus 123 2x
WKQ       Spreadsheet                                     Quattro
                                                          Lotus 1-2-3 version
WKS       Spreadsheet                                     1A - Lotus Symphony
                                                          1.0, Microsoft Works
WKS       Workspace                                       Xlisp
WKZ       Spreadsheet format                              Dos Navigator
WLK       Graphics                                        Virtus Walkthrough
WLK       Walk Through for any game                       many
WMA       Windows Media Audio audio file
WMC       Backup of startup files by Windows MathCad      MathCad
          autoexec.wmc
WMC       Macro file                                      WordPerfect for Win
WMC       Text file                                       WordMARC
WMDB      Windows Media Player database                   Windows Media Player
WMF       Windows MetaFile vector graphics
                                                          Blizzard
WMO       WoW Map Object                                  Entertainment games
                                                          (World of Warcraft/
                                                          Warcraft series)
WMP       Graphics (Windows Magic Icon Palette)
WMV       Windows Media Video video file
WN        Text                                            NeXT WriteNow
WNF       Corel Draw Font File                            CorelDraw
WOA       Swap file                                       Windows 3.x
WOC       Organization                                    Windows OrgChart
WOFF      Web Open Font Format
WOFF2     Web Open Font Format
WORKFLOW  Workflow                                        macOS
WOW       Music (8 channels)                              Grave Mod Player
WP        Word Perfect Format                             WP
WP5       Document                                        WordPerfect 5.x
WPD       Document                                        WordPerfect 6.0 -
                                                          PFS:WindowWorks
WPD       Windows printer driver (uninstallable)          Windows
WPF       Fax                                             WorldPort
WPF       Form                                            WordPerfect
WPG       WordPerfect Graphics vector graphics            DrawPerfect
WPJ       Watcom C/C++ IDE project                        IDE.EXE
WPK       Macros                                          WordPerfect for Win
WPL       MediaRack Wave Playlist                         MediaRack
WPL       Windows Media Playlist                          Windows Media Player
WPM       Macros                                          WordPerfect
WPS       Text document                                   Microsoft Works
WQ!       Compressed spreadsheet                          Quattro Pro
WQ1       Spreadsheet                                     Quattro Pro
WR1       Spreatsheet                                     Lotus Symphony 1.1 -
                                                          1.2 - 2
WRD       Template                                        Charisma
WRI       Write editor format                             Write - WinWord
WRK       Spreadsheet                                     Lotus Symphony 1.0
WRL       VRML file
WRP       Archive                                         Amiga WARP
WRS       Windows Resource e.g. might indicate error if   WordPerfect for Win
          word cannot open
WS        APL Worksheet
WS        Text file                                       WordStar 5.0-6.0
WS2       Text file                                       WordStar 2000
WS7       RS7 Setting                                     Redshift 7
WSD       Document                                        WordStar
WSF       Windows Script File                             Microsoft Windows
                                                          Script Host
WSP       Workspace                                       Fortran PowerStation
WSQ       Wavelet-packet Scalar Quantization Format
WSRC      X-wais source
WST       Text file                                       WordStar
WSV       Keysight SystemVue Workspace file               Keysight SystemVue
WTR       Working Timetable rules file                    Simsig
WT        Parameter or data dump file                     WildTangent or
                                                          MongoDB
WTT       Working Timetable timings file                  Simsig
WTF       World of Warcraft Data File                     World of Warcraft
WTF       WinTaper Data
WV        WavPack
WWB       Button bar for document window                  WordPerfect for Win
WWF       WWF Document Format
WWK       Keyboard layout                                 WordPerfect for Win
WXH       Program/Script File                             WaxHtml Web
                                                          Programming Language
WXP       Document                                        EXP for Windows
WZ        Wizet game archive file                         Wizet/Nexon
                                                          MapleStory
                                                          Department of Defense
WZA       Encrypted archive file                          Encryption Wizard
                                                          (Public Edition)

X      Archive                         X1.EXE
X      AVS X image file                SDSC Image Tool
X      DirectX 3D object
X      LEX source code file
X      XBasic Source code file         Xbasic
X3D    x3d and xdart Formats
XA     XA audio file                   used in SimCity 3000 by Maxis, also by
                                       Sony PlayStation
                                       Files created by Xara Photo & Graphic
XAR    Xara graphics file              Designer (formerly Xara Xtreme and Xara
                                       Studio); early versions used the
                                       extension ART
XBE    Xbox Executable                 Xbox
XBM    X11 Bitmap graphics file
XLBL   extensible Business Reporting   Business Reporting
       Language
XCF    Gimp image file                 GNU Image Manipulation Program
XCK    Extended crack file (usually
       text)
XCL    Xtree for Windows Script file   Xtree for Win
XDF    OS/2 extended disk format image XDFCOPY.EXE
XDM    Directory Manipulator for       Xenotech Research Labs
       32-bit Protected Mode
XE     Xenon - for Associative 3D      Ashlar-Vellum
       Modeling
XEPH   PixInsight Solar System         PixInsight
       Ephemeris Data File
XEX    Xbox 360 Executable File
XFN    Printer font                    Xerox 4045 - Ventura Publisher
XFR    Ventura Publisher Bitmap Editor
       Font file
XFT    24 pin printer font             ChiWriter
XI     FastTracker 2 instrument file   AWAVE
XIF    Xerox Image Format              Pagis Pro 2.0 and 3.0
XISB   Extensible Image Serialization  PixInsight (see XISF 1.0 Specification)
       Format (XISF data blocks file)
XISF   Extensible Image Serialization  PixInsight (see XISF 1.0 Specification)
       Format (monolithic XISF file)
XISH   Extensible Image Serialization  PixInsight (see XISF 1.0 Specification)
       Format (XISF header file)
XOSM   PixInsight Project File         PixInsight
XLA    Add-in macro sheet              Microsoft Excel
XLA    XLib Archive                    xlibpas2.zip
XLB    Microsoft Excel Toolbar         Microsoft Excel
XLC    Microsoft Excel Chart           Microsoft Excel
XLD    Microsoft Excel Dialog          Microsoft Excel
XLF    Extensible LADAR Format         LadarSIM
XLK    Microsoft Excel Archive         Microsoft Excel
XLL    Microsoft Excel Dynamic Link    Microsoft Excel
       Library
XLM    Microsoft Excel Macro File      Microsoft Excel
XLR    Microsoft Works                 Microsoft Works
XLS    Microsoft Excel Spreadsheet     Microsoft Excel
XLSB   Microsoft Excel 2007 Binary     Microsoft Excel 2007 (see Microsoft
       Workbook (BIFF12)(Spreadsheets) Office 2007 file extensions)
       Microsoft Excel 2007            Microsoft Excel 2007 (see Microsoft
XLSM   Macro-Enabled Workbook          Office 2007 file extensions)
       (Spreadsheets)
XLSX   Office Open XML Workbook        Microsoft Excel 2007 (see Microsoft
       (Spreadsheets)                  Office 2007 file extensions)
XLT    Microsoft Excel Template        Microsoft Excel
XLT    Translation table               Lotus 1-2-3 - Symphony - Procomm Plus
XLV    Microsoft Excel Module          Microsoft Excel
XLW    Microsoft Excel Workbook        Microsoft Excel
XM     FastTracker 2 extended module   AWAVE, Mod4Win, FastTracker,
                                       ImpulseTracker
XM     Music format                    FastTracker 2 - Cubic Player
       Assisted contact lists file
XMC    format, based on xml and used   Classmates iPhone app
       in kindergartens and schools
XMOD   Monarch Model                   Monarch Professional
XMI    Compressed eXtended MIdi music
XML    eXtensible Markup Language file
XMF    eXtensible Music Format
XMPZ   XML Miradi Project Zipfile      Miradi
XMV    video                           Xbox
XNF    Standard Network File form
XNK    Microsoft Outlook               shortcut to Outlook entities
Xnn    Secondary indexes               Borland Paradox
XOF    RenderMorphics
XP     eXtended Pattern                FastTracker 2
XPL    X-Plane system file             Laminar research
XPM    X11 Pixel Map graphics file
XPO    Microsoft Dynamics AX Export
       file
       Open XML Paper Specification /  open standard document format initially
XPS    OpenXPS                         created by Microsoft and similar in
                                       concept to Adobe PDF files
XQT    Executable file                 Waffle
XQT    Macro sheet                     SuperCalc
XRM-MS XrML Digital License            SuperCalc
XSD    XML schema description
XSF    data                            Microsoft InfoPath file
XSF    data                            Microsoft InfoPath file
XSPF   XML Sharable Playlist Format
XSL    XSL Stylesheet
XSLT   XSLT file
XTB    External translation table      LocoScript
XTP    XTreeGold overlay               XTreeGold
XVF    Xyngo Video File                Xyngo Video Board
XWD    Xerox DocuWorks file (RTF       DocuWorks
       internal?)
XWD    X Window System window dump     SDSC Image Tool
       image graphics file
XWK    Keyboard mapping                Crosstalk
XWP    Session                         Crosstalk
XWP    Text file                       Xerox Writer
XX     XX-encoded file (ASCII)         XXDECODE
XXE    XX-encoded file (ASCII)         XXDECODE
XXX    Singer Embroidery Format        Embroidermodder
XY     Text file                       XY Write
XY3    Text file                       XYWrite III
XYW    Text file                       XyWrite III
XYZ    Molecular coordinates           XMol, RasMol
       a lossless data compression
XZ     file format incorporating the   xz
       LZMA/LZMA2 compression
       algorithms.

Y      Archive (Amiga)                  Yabba
Y      YACC grammar file                Yacc/Bison
YAL    Data custom/nature.yal           Arts & Letters
YAML   Yaml source file                 YAML (data serialization language)
YC     Archive                          YACC (YAC.EXE)
YLIB   Yookoo Music Library Backup File Yookoo Media Player
YMP    Yast Meta Package                YAST2 (SUSE Linux Package Manager)
Ynn    Secondary index                  Borland Paradox
YOOKOO Yookoo Playlist                  Yookoo Media Player
YRD    Yard Tracks File                 FYM
YST    Data                             YASRT Raytracer scene
YUV    Graphics format (YUV)
YY     Bison grammar file               Bison
YZ     Archive                          YAC

Z       Archive                             WinZipNT - compress - pack
Z01-Z99 Split WinRAR Archive
Z2S     Zoo Tycoon 2 saved game             Any game in the Zoo Tycoon 2 series
Z3      Infocom game module
Z3D     Zmodeler-file                       Zmodeler 1 & 2
Z64     Nintendo 64 ROM                     Nintendo 64 emulators
Z64     Nintendo 64 ROM                     Project64 Nintendo 64 emulator
Z80     Snapshot                            ZX Spectrum emulator by g.a.lunter
ZAD     ZFax digitized voice file           ZFax
ZARGO   UML model project file              ArgoUML
ZCC     Cutpath for Zund digital cutting    Zund Cut Center
        systems
ZDG     Compressed ZiffNet text document    Z-view
ZED     BitTorrent Link                     Podmailing
ZER     Data file
ZIF     Zoomable Image Format
ZIP     Archive                             PKZip - WinZip - Mac OS X
ZOO     Zoo Tycoon saved game               Any game in the Zoo Tycoon (first)
                                            series
ZS      Script for Minecraft mod            Minetweaker Minecraft Mod
        MineTweaker^[8]
ZTD     Zoo Tycoon data                     Zoo Tycoon
ZUR     High level compressed file
ZUZ     Cost estimating file                ZUZIA ZUZIAbim
ZYP     Reason Subtractor Patch File        Propellerhead Reason
ZZT     ZZT World                           Any world created using the ZZT
                                            editor