$ git clone -n https://src.fedoraproject.org/rpms/sar2.git /var/lib/mock/f45-build-35557-696/root/chroot_tmpdir/scmroot/sar2
Cloning into '/var/lib/mock/f45-build-35557-696/root/chroot_tmpdir/scmroot/sar2'...
$ git fetch origin 692a036921a1e2cc6e4248afd62da752ddd91671:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/sar2
 * [new ref]         692a036921a1e2cc6e4248afd62da752ddd91671 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 692a036 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild