I've historically been the maintainer of shared-mime-info for around 15 years, and script/freedesktop.org.xml looks like it's a copy of the database shipped with shared-mime-info, which is released under the GPL, with shared-mime-info's translators work merged in, and the GPL header removed.
The license that you're shipping mimemagic under (MIT) isn't compatible with shared-mime-info's.
There are a number of possibilities to fix this problem:
- change the mimemagic license to be GPL compatible
- parse the XML file that shared-mime-info ships at runtime, and don't ship it in a codebase with an incompatible license
Using a GPL file as a source makes your whole codebase a derived work, making it all GPL, so I think it's pretty important that this problem gets corrected before somebody uses it in a pure MIT codebase, or a closed-source application.
You will also need to re-add the GPL header to the shared-mime-info XML file as a matter of urgency. It was stripped in release tarballs by the tool used to merge translations, but is visible in the .in version of the same file.