It doesn't look like a strict review is being
done, there are no
guidelines as to what appropriate history should look like, what to
tell people who are denied (can they ask again? how long do they
wait?), how long someone should be up for review (I've seen a day, an
hour, 24 hours, a "few hours" etc.).
I think that's intentional to reduce bureaucracy. The way I understand
it, the idea is that a single admin is enough to promote, there is no
need to give anyone else a chance to review. If an admin decides, in
their judgement (which is considered trustworthy, otherwise they
wouldn't have passed RfA), that the person can be trusted with
rollback, then they can give it to them. There isn't meant to be a
complicated and detailed review process.