The first question was "How would you do any of the below?" which is easier to answer when it's apparent what problem an extension is solving.
The second question was "Where is this git-time-machine equivalent?" which is easier to answer when one knows what a user is expected to accomplish by using it, specifically the graphical part.
I think the Atom developers are doing the right thing now by focusing on performance more than useless graphics. Right now I recommend vscode to other people even though I'll probably always use emacs myself.
