Any specific example?
(just to be sure you are actually talking about free software instead of open source...)
Anyway, I stink I should spend some time to write a tutorial on how to setup a #Fossil multi project forge. It's my #dvcs of choice these days given how cheap, easy and featureful it is, in a single statically compiled executable with no dependencies.
Compared to git-based forges it's way simpler and more featureful despite having a web 1.0 interface (something I love, but some don't feel cool enough).
Here a full feature example https://fossil-scm.org/home/doc/trunk/www/index.wiki
Here one of my projects using it: https://code.tesio.it/p/self-hosting/doh.cgi/dir?ci=tip
(Note that some hate my #HackingLicense, despite it gives users that accept it as a binding contract more rights and permissions than any other existing #copyleft: not a #opensource license for sure, arguably a free software license since it forbids any use of the covered work that would limit the freedoms of others... yet as a contract, it is a first attempt against #GenAI corporations' abuses...)