ET: Legacy is based on the source code of Wolfenstein: Enemy Territory which was released under the GPLv3 license. The main goal of this project is to fix bugs, remove old dependencies and make it playable on all major operating systems while still remaining compatible with the ET 2.60b version and as many of its mods as possible.
Spearmint is a fork of the ioquake3 engine with fixes and features that don't fit in ioq3 for one reason or another. Created to be a better base engine for standalone games. Spearmint is not compatible with quake3 game code (QVMs/DLLs/SOs/DYLIBs), demos, or network packets.