I've asked our map people to help you out here. eadingas is probably the one who worked on this.

Looks like there are 3 sections of the file changed from vanilla. Everything after
Code:
inaccessable modifies default
looks completely new. Also, a couple of lines earlier in the file have been changed:

old
Code:
texture		env_map			battlefield/envmaps/grass.dds
has been changed to
Code:
texture		env_map			battlefield/envmaps/desert.dds