I'll submit this patch upstream soon:
https://github.com/avar/file/tree/add-sereal
Any comments on the file(1) output before I do so? And also we did
agree on application/sereal as a MIME type, didn't we? At least that's
what we're using in work code with a reference to
http://www.rfc-editor.org/bcp/bcp178.txt
See this in the main repo at work:
$ git log --reverse -p -Gapplication.*sereal -- $(git grep -l
application.*sereal)