Sorry, if I posted posts with 2 links due to member trust level limitations.
I digged more stuff:
- Quake 3 game-module documentation (Q3 programming dictionary/glossary):
https://web.archive.org/web/20120530215638/http://www.soclose.de/q3doc/index.htm
- The Reaction Factory - Quake III & Team Arena Tutorials (a dead site):
https://web.archive.org/web/20070226055434/http://rfactory.org/
- Q3 Documentation Project (a thread from a lost part of Quake3world forums):
https://web.archive.org/web/20090421235225/http://www.quake3world.com/ubb/Forum4/HTML/005563.html
- Quake III: Team Arena menu guide (looks like focused in cgame, HUD and menu):
https://icculus.org/~phaethon/q3tamenu/q3tamenu.html
→ Code3Arena similar copies:
https://www.per-thormann.de/quake-3-arena-coding-tutorials/
https://web.archive.org/web/20180923060300/http://wiki.ioquake3.org:80/Mod_Making_101