$ git clone -n https://src.fedoraproject.org/rpms/grubby.git /var/lib/mock/f45-build-13069-446/root/chroot_tmpdir/scmroot/grubby
Cloning into '/var/lib/mock/f45-build-13069-446/root/chroot_tmpdir/scmroot/grubby'...
$ git fetch origin c31337f4ba760fe562d3b2414fb99e760975ca69:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/grubby
 * [new ref]         c31337f4ba760fe562d3b2414fb99e760975ca69 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c31337f Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild