$ git clone -n https://src.fedoraproject.org/rpms/xplanet.git /var/lib/mock/f45-build-39063-731/root/chroot_tmpdir/scmroot/xplanet
Cloning into '/var/lib/mock/f45-build-39063-731/root/chroot_tmpdir/scmroot/xplanet'...
$ git fetch origin ba8c06aa058fd915e5ad811c61bb7ff52a158002:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xplanet
 * [new ref]         ba8c06aa058fd915e5ad811c61bb7ff52a158002 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ba8c06a Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild