Originally Posted by Light
They are using the Lunia Developer Software, it decrypts and allows editing of the file contents. No one ever gets these programs, and sometimes it's custom made.
If I'm not mistaken most game companies do this nowadays. They use unique file types that are associated only with there game to prevent piracy of there material and etc. Although they're some dedicated people out there who will build their own decrypters. (I.E. Crackers/Hackers)