$ git clone -n https://src.fedoraproject.org/rpms/root-tail.git /var/lib/mock/f45-build-34605-688/root/chroot_tmpdir/scmroot/root-tail
Cloning into '/var/lib/mock/f45-build-34605-688/root/chroot_tmpdir/scmroot/root-tail'...
$ git fetch origin 53abd4e5d91c28f6217cd74d115d38db8c3d4f94:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/root-tail
 * [new ref]         53abd4e5d91c28f6217cd74d115d38db8c3d4f94 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 53abd4e Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild