I would like to briefly interrupt this discussion (which I do not wish to get involved in so don’t @ me) with TOUHOU FUN FACTS.
When it comes to the direct usage of Touhou stuff (that is to say, anything found in the original Touhou games), ZUN has declared that anything you make that’s self-published is allowed to use the source material in any way without even notifying him. However, he does specify that copyright of assets created by other people based on his stuff remains with them, which is what makes this fun fact irrelevant to the discussion at hand, hence why it’s just a fun fact.
What this does mean is you could probably toss anything from a direct Touhou game into the repo if you wanted to. Would you want to? Maybe if it was from one of the fighting games lol.