When you merge, us
refers to the branch you’re merging into, as opposed to them
, the branch to be merged.
When you rebase, us
refers the upstream branch, and them
is the branch you’re moving about. It’s a bit counter-intuitive in case of a rebase.
The reason is that Git uses the same merge-engine for rebase, and it’s actually cherry-picking your stuff into the upstream branch. us
= into, them
= from.