mp3medias ?

Just noticed something today.  Probably always been like that, but ...

I routinely rip to FLAC, but today when I fired up my mac to edit some metadata on a Toots Thielemans box set I recently acquired, I noted that the 'kind' as reported by mac finder was 'mp3medias'.   File type is still quite clearly FLAC (usual .flac extension).   I assume that macos thinks flac is some kind of mp3, but why?  I'm sure my files are flac, so it must just be a mac oddity.

Incidentally, Toots was a superb harmonica player.