For similar ability with an existing wiki you can use something like https://github.com/Git-Mediawiki/Git-Mediawiki to access the content of a mediawiki instance using the git client tools.
It takes a really long time to do an initial clone (sometimes many hours), and because it is still driving git, if the clone fails, it fails. Even after the initial clone, fetches can take quite a long time and there are many bugs.
I use it myself for archiving mediawikis.
Encycla seems much more git-first, which is also awesome.