Mimetype detected by libmagic is inaccurate

If I create file in Microsoft Word (Mac, version 16.17) and then check its mimetype using libmagic on the command line I get the following output on Mac

$ file --mime file_created_in_word.docx
application/vnd.openxmlformats-officedocument.wordprocessingml.document

However, files created by python-docx get a different mimetype

$ file --mime file_created_by_python-docx.docx
application/octet-stream

This affected me in some testing code that wanted to check that the document that was output was the correct type. Can anyone give insight into this?

[xsduan]

Here’s the relevant source file: https://github.com/threatstack/libmagic/blob/1249b5cd02c3b6fb9b917d16c76bc76c862932b6/magic/Magdir/msooxml

Apparently the file order is important. You can test this by renaming the first 4 characters of the third file (the first ascii text after the 3rd PK\x03\x04 in the file) to word/, and it’ll register correctly as word 2007. python-docx seems to put docProps/core.xml as the 3rd file (because it puts all the files in alphabetical order).

[kyprifog]

I’m having this same issue: https://github.com/ahupp/python-magic/issues/208