[vildoran]

We have an in-game application process that can be used, though typically we are targeting players that already have knowledge of the game and how certain systems work.

You are correct that the source code isn't public. There are two levels of source code, the in-game code (quests, regions, etc., written in LPC in our case) and the MUD driver code (C). The in-game code has been leaked a few times by some of the developers, and so many of the people that want it have it by this point.

The MUD driver we started with (TMI-2 1.1.1 on MudOS v22pre8 if you want to look it up) is heavily modified now, but the original source is out there.