@jayarejay is truly a friend to all. From this thread and the details provided by @jayarejay I found my way to this code: https://github.com/file/file/blob/9b2538dcff625a315435fa48e4117579173f5909/magic/Magdir/sql#L84 And then around line 127 is some very familiar looking chunks :) So, it appears the "correct" answer is that folk (ie: me) who want their application file formats to be recognized should send a patch for libmagic and file(1) -- and that the magic.txt file that is part of the SQLite codebase is really just a hint/pointer/clue of what to put in libmagic Perhaps the SQLite codbase magic.txt file could be updated to point FNG like me to go elsewhere for submitting the patch (I assumed SQLite maintained their list and worked with up-stream to get into file(1) codebase) Also, I think this sentence has the numbers backwards? ""The user_version is very similar to application_id except that it is stored at offset 68 instead of offset 60"" user_version is at 60 and application_id is at 68