Seems to have no usable documentation and the github repo has basically no activity in a long time

Don't confuse "lack of activity" with "broken." The program is considered complete. I recently moved everything to FPC 3.0, see https://github.com/MerlijnWajer/Simba/tree/fpc-3.0. The other work going on is language features for the scripting engine.

Most functionality is documented at http://docs.villavu.com/simba/.

I don't confuse these things. I just stated that there isn't much activity. But thanks to your answer I took a second look. My problem was that the first impression of the documentation site wasn't/isn't that good IMO. I skimmed the first (quite a few) pages of the documentation and didn't find anything that gave me a first impression what this program/language looks like. You know some kind of small (or not so small) sample code. Then I skipped to the "Tutorial" section which consists of empty pages. Discouraged by that I missed the much better "Scripting Reference" section. So I suggest to at least remove the empty Tutorial section until there is actual content and/or simply link to the examples in the repository

I'm not sure why you'd mention it otherwise.

We were considering moving the documentation to GitHub so people were more likely to contribute. There is a function viewer and many of the functions are documented in the source. The autogeneration was abandoned before it was set up because the program does what it was built to do.

Part of it is you need to have some idea what you want to do with the program before you start. Most of the tutorials exist on villavu.com's forums with the goal of automating gameplay.