$ git clone -n https://src.fedoraproject.org/rpms/mongo-c-driver.git /var/lib/mock/f41-build-847440-163983/root/chroot_tmpdir/scmroot/mongo-c-driver
Cloning into '/var/lib/mock/f41-build-847440-163983/root/chroot_tmpdir/scmroot/mongo-c-driver'...
$ git fetch origin a86c880eb5abb915e170d6d3ad0a90e5eef9aea2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mongo-c-driver
 * [new ref]         a86c880eb5abb915e170d6d3ad0a90e5eef9aea2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a86c880 v1.27.6