+
The <src> is often the name of the branch you would want to push, but
it can be any arbitrary "SHA-1 expression", such as `master~4` or
-`HEAD` (see linkgit:git-rev-parse[1]).
+`HEAD` (see linkgit:gitrevisions[1]).
+
The <dst> tells which ref on the remote side is updated with this
push. Arbitrary expressions cannot be used here, an actual ref must