Some match values of type string in freedesktop.org.xml contain octal numbers written as leading '\' and following octal digits. E.g. "\177ELF". There's no mention of this format in Shared MIME-info Database spec and seems not to be a part of XML format.
Fixed in git, but website not updated yet (I'll do it from the machine that has the setup, next week).
(In reply to David Faure from comment #1)
> Fixed in git, but website not updated yet
I also suggest that you add a note whether xml entity decoding must appear before or after decoding escaping characters to avoid ambiguity.