At least last I used it (for a one-man documentation attemmpt), it was built entirely into the HTML file you're reading / editing: All the Wiki functionality was JavaScript, stored within the actual content page itself. Works great for single-person use, dunno about many. Guess it depends on the size of your team.
Also, not sure if it's changed: The current Web page talks about "TiddlyDesktop is an app for working with TiddlyWiki files..." and "Don't attempt to use the browser File/Save menu option to save changes (it doesn't work)" -- which AFAICR used to be exactly the way to do it. And I can't recall there being any app at all. So Idunno...
But if you want to spend some time looking into it:
https://en.wikipedia.org/wiki/TiddlyWiki
https://tiddlywiki.com/
Also, not sure if it's changed: The current Web page talks about "TiddlyDesktop is an app for working with TiddlyWiki files..." and "Don't attempt to use the browser File/Save menu option to save changes (it doesn't work)" -- which AFAICR used to be exactly the way to do it. And I can't recall there being any app at all. So Idunno...
But if you want to spend some time looking into it:
https://en.wikipedia.org/wiki/TiddlyWiki
https://tiddlywiki.com/