As shown in D1430 our processes for landing patches coming from external contributors aren't great (as in: not terribly user friendly).
I think historically asking contributors to just "git push" once their diffs are accepted used to work, but even if it is the case that isn't a great workflow, so I don't think we should try to fix it that way. Rather, we should make it trivial for us, core developers, to land accepted patches.
Again, I think some repos allow landing via the Phabricator web UI, e.g., swh-web, but not all of them to.
We should fix this, making sure all repos allows via-the-web landing and make sure all repos created in the future allow that too.
cc: @olasd as I think he is the person who made the magic possible for swh-web.