Unvanquished (https://unvanquished.net) became the new "Tremulous" (different engine, etc.), also has bots.
Read more about it here: https://wiki.unvanquished.net/wiki/Bot_design
- navigation, which is done with a combination of A* or Dijkstra and navmeshes
- decision, which is done with the paradigm of behavior trees
- computer vision, to complete what navmeshes can not provide
Despite the term "computer vision", it is still not AI.
I will quote the "Navigation" and "Computer vision" section from the site I linked above:
> All bots should be able to reach any part of the map that does not require special training.
> Bots should be able to detect any enemy in their FoV. It would be nice to have bots not being too good at finding hidden buildables on the roof. This makes hiding eggs unfun and next to impossible in the current state. Unless they are placed outside of a navmesh, in which case bots are totally unable to discover them.
There is a pull request that implements the use of "beacons" for bots which is used to locate buildables: https://github.com/Unvanquished/Unvanquished/pull/2683
There was no "computer vision" in the Tremulous bots, FWIW.
In Tremulous, they used waypoints only, so has nothing to do with AI either.
Bots in Unvanquished are quite human-like and there are plans to add personalities (if they did not add them already) and there is no AI there either.
TL;DR: You can have bots that work quite damn well and human-like without AI/ML.