Sonic Xtreme .def files?

[The64thGamer]

So, Sonic Xtreme's map files are in a .def format, is there any way to convert that to an obj?
I can't seem to find anything on the internet about .def files, is this a Sonic Xtreme exclusive file type?

Here is one of the .def's I want to rip if you need a look a it.