According to this: https://docs.unrealengine.com/latest/INT/Engine/UI/SourceControl/index.html only Perforce and SVN are. I’m a bit confused because Git is definitely enabled by default along with the other two. PlasticSCM will hopefully make it there as well, but that’s another story.
By the way, this was a really awesome addition because I actually had to make something similar for all the new devs that I’ve worked with on any of my projects using Source Control, so now I can effectively cut out this part from mine, link this and just have the rest.
But yeah, I suppose some clarification on what’s “supported by default”. Thanks!