OpenArena Expanded is the development version of OpenArena. Its purpose is both
to create improve the basic OpenArena gameplay but also to create a good
starting point for any OpenArena or Quake III:Arena mods.

It does not include engine or platform specific code. The source code is
GPL v2 or later but some of the tools are not.

WWW: http://code.google.com/p/oax/