For now there is only a #ask-here category for all questions. Tags will help categorizing as well.
The idea here is to avoid a skeleton of categories before knowing how many questions are we going to get about which topics, and which areas will be well covered with contributors answering questions.
If we start seeing a good volume of activity related to certain area (i.e. #bots) then we could spin off a category. Or if the maintainers of a certain area (i.e. #bots ) say that they have decided to organize their developer support here, then we can also arrange for that.
Do you find this approach reasonable? As with many details of this pilot, we are applying common sense and improvisation interchangeably.