On another team I was on, in 2002 using CVS, we had an upside-down solo cup as a base for a small plastic pirate flag. If you were ready to commit, you grabbed the pirate flag as a mutex on the CVS server. Of course, this turned competitive… and piratical.
I despair about long-lived git feature branches and pull requests. The pull request model is fine for open source development, but it’s been a move backwards for internal development, from having a central trunk that a team commits to several times a day. The compensating factors are git’s overall improvements (in speed and in principled approach to being a content addressable filesystem) and all of the fantastic improvements in linters and static analysis tools, and in devops pipelines.