But these pages are not easy to find, I had to use search.
This should be mentioned on the pricing page.
TBH all these features on Gold and Ultimate for free are game changers (specially Gold since you won't need to manage and install so many things that used to be many different systems), GitLab should advertise it more.
https://marc.info/?l=git&m=111377572329534
I don't know about 'git branch', but it looks like 'git merge' wasn't a thing
edit: from searching a bit, it appears that it had branches on June of the launch year, dunno if it had those on release.