Consider using an MIT licensed mime db?

[patsplat]

Is there a reason against using an MIT licensed json db from mime-db, rather than continuing to use the GPL free desktop mime db?

https://github.com/jshttp/mime-db

Using a compatible license should allow the derivative file to be distributed, and remove the need for environment variables etc.

Would such a PR be welcome?

[patsplat]

mime-db provides the extensions but not the magic

the magic needs to come from another source, perhaps http://www.darwinsys.com/file/

[animeavi]

Marcel used Apache Tika as the source of the DB (and used code from this gem to parse it)
rails/marcel@2e58d19