diff --git a/src/core/lib/FileSignatures.mjs b/src/core/lib/FileSignatures.mjs
index 17b17f23..5f5c0d2f 100644
--- a/src/core/lib/FileSignatures.mjs
+++ b/src/core/lib/FileSignatures.mjs
@@ -1008,8 +1008,7 @@ export const FILE_SIGNATURES = {
                 0: 0x7b,
                 1: 0x5c,
                 2: 0x72,
-                3: 0x74,
-                4: 0x66
+                3: 0x74
             },
             extractor: extractRTF
         },