$ git clone -n https://src.fedoraproject.org/rpms/rocksndiamonds.git /var/lib/mock/f41-build-746227-13353/root/chroot_tmpdir/scmroot/rocksndiamonds
Cloning into '/var/lib/mock/f41-build-746227-13353/root/chroot_tmpdir/scmroot/rocksndiamonds'...
$ git fetch origin 4fbe59994b1fd3fce6510882b6f3db7a02bd730c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rocksndiamonds
 * [new ref]         4fbe59994b1fd3fce6510882b6f3db7a02bd730c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4fbe599 Eliminate use of obsolete %patchN syntax (#2283636)