$ git clone -n https://src.fedoraproject.org/rpms/velocity.git /var/lib/mock/f41-build-1037835-18818/root/chroot_tmpdir/scmroot/velocity
Cloning into '/var/lib/mock/f41-build-1037835-18818/root/chroot_tmpdir/scmroot/velocity'...
$ git fetch origin 7efde23aa196d715ea53d0bb9adcd75595abd478:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/velocity
 * [new ref]         7efde23aa196d715ea53d0bb9adcd75595abd478 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7efde23 Switch to a newer %patch syntax