$ git clone -n https://src.fedoraproject.org/rpms/libcerf.git /var/lib/mock/f45-build-15970-481/root/chroot_tmpdir/scmroot/libcerf
Cloning into '/var/lib/mock/f45-build-15970-481/root/chroot_tmpdir/scmroot/libcerf'...
$ git fetch origin fa9d2b1fdc3ecce1e58a40ccd22c0b1ba084e2f2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libcerf
 * [new ref]         fa9d2b1fdc3ecce1e58a40ccd22c0b1ba084e2f2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fa9d2b1 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild