Notes to self.
I have no idea what might have led to conflicts involving files such as /usr/src/UPDATING
…
% git -C /usr/src stash
% gh repo sync grahamperrin/freebsd-src && git -C /usr/src pull --ff-only && git -C /usr/src pull --ff-only freebsd main
✓ Synced the "grahamperrin:main" branch from "freebsd:main"
Already up to date.
From https://git.freebsd.org/src