$ git clone -n https://src.fedoraproject.org/rpms/mcpp.git /var/lib/mock/f42-build-3273570-41312/root/chroot_tmpdir/scmroot/mcpp
Cloning into '/var/lib/mock/f42-build-3273570-41312/root/chroot_tmpdir/scmroot/mcpp'...
$ git fetch origin 959bf968454956f3a6347c5b8e32061912a3e396:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mcpp
 * [new ref]         959bf968454956f3a6347c5b8e32061912a3e396 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 959bf96 Retired: https://lists.fedoraproject.org/archives/list/devel-announce@lists.fedoraproject.org/thread/DRIWVJ7BVL3KVVX5TLC36LJPDMAO72HF/