$ git clone -n https://src.fedoraproject.org/rpms/mercurial.git /var/lib/mock/f41-build-side-2-python-2708436-30473/root/chroot_tmpdir/scmroot/mercurial
Cloning into '/var/lib/mock/f41-build-side-2-python-2708436-30473/root/chroot_tmpdir/scmroot/mercurial'...
$ git fetch origin 9ee6346e8f42002676d4c943a0775ed4040189ff:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mercurial
 * [new ref]         9ee6346e8f42002676d4c943a0775ed4040189ff -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9ee6346 Drop upstreamed demandimport patch.