New comment by Duncaen on void-packages repository

https://github.com/void-linux/void-packages/issues/30486#issuecomment-826330127

Comment:
Looks like its either using `mimetype` or `file`, `file` will say `video/m4a` and `mimetype` from `perl-File-MimeInfo` will print `audio/m4a`.

In pacman `perl-File-MimeInfo` is an optional dependency, so you probably had this installed.