> Let's try and search for more candidates.  The two word ones are clunky

+1.

We want to balance a clean UI with one that is clear and obvious what
it does.  What about the balloon help for those?

I feel the balloon help is very good UI feature to let the user "drill
deeper" into the UI widgets to understand what they do, without
intruding too much into the UI once the buttons are learned.

I think we should keep utilizing this capability of the IDE to
preserve the single-word elegance of whist expanding with any
necessary clarity in the balloons.

Presently, those balloon hints say, "Keep the selected change" and
"Reject the selected change."  If we need to choose new button labels,
we should do it together with these balloon helps.