$ git clone -n https://src.fedoraproject.org/rpms/relval.git /var/lib/mock/f45-build-34466-687/root/chroot_tmpdir/scmroot/relval
Cloning into '/var/lib/mock/f45-build-34466-687/root/chroot_tmpdir/scmroot/relval'...
$ git fetch origin 083eed524f54376bd6f5f7254333c62db2b60cc3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/relval
 * [new ref]         083eed524f54376bd6f5f7254333c62db2b60cc3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 083eed5 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild