It doesn’t save anything. That save option is there but it will save the wiki to the users local machine not back to your GitHub repo. If i understand your question correctly. However you can hide the option to save…I have seen the functionality somewhere…I will look for it and come back to you. Take a look at this for starters ; How could I activate a "read-only" mode over "http://" or "https://" automatically? and Wikitext solution for hiding buttons/tabs ("read only") - contributions welcomed and no doubt there are countless other ways to disable / hide the functionality…If you wait i’m sure someone with more experience will chip in and you’ll have the answer to your problem…but these give you something to think about in the meantime 