Odamex
From ZDoom Wiki
Odamex is a multiplayer-oriented port based on csDoom which obtained Randy Heit's permission to relicense the ZDoom 1.22 code they've kept under the GPL. Because the source code for Heretic and Hexen was not under this license at the time, all the Raven Software code was removed (along with some code actually written by Randy which they could have kept).
