$ git clone -n https://src.fedoraproject.org/rpms/python-billiard.git /var/lib/mock/f41-build-side-1-2880458-34463/root/chroot_tmpdir/scmroot/python-billiard
Cloning into '/var/lib/mock/f41-build-side-1-2880458-34463/root/chroot_tmpdir/scmroot/python-billiard'...
$ git fetch origin 7ab9d2228e9702532384a4905d1eb45b9758b3de:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/python-billiard
 * [new ref]         7ab9d2228e9702532384a4905d1eb45b9758b3de -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7ab9d22 Update to 4.2.1 (close RHBZ#2314005)