That's correct, most of the authors and artists we work with are freelance and bring us projects they would like us to help with. Most of which are for Troika! but not all.
Troika! is an entirely open licence game and can be used by anyone to create anything they like just by including a short piece of text we supply on the files for the main game, in the case of Longshot City it has taken a few more liberties in adapting the rules so we need to check in with him to ensure we're getting it right for you.