Can it be done with Twine-created HTML? They look pretty different from regular ones, and I still have to port it onto Twine to create a second one, so GitHub merging is not much useful.
The raw files on your system should be fine to manage on github, youd just have to use Twine to edit and stuff. It wouldnt use it for dev work, since it does need importing, but to post updates for others to play with it should be fine. Youd just commit any changes after you finish an update.