Maybe grandpa already knows, but in Pharo's case, there is Iceberg. It's a Git interface that's included in default Pharo images that understands Pharo's packages, and so on. You can push your stuff to Github etc. and teams can work together that way.

I've never worked in a team in a Pharo projects, but I imagine it works well somehow. There's ~75 contributors to the 8.0 release.