I'd search the magic file at this system.
I think this guy wrote a on liner for converting and used a magic file entry to associate the file with that script.
Some of the used locations:
/usr/magic # Debian
/usr/share/magic # Fedora
So first you should find the proper type:
Then list the magic file and grep that entry.
A bit strange sounds the pasted URL.
It seems the guy who set this up modified somewhere somehow the DE...
(but that is an other problem..)