$ git clone -n https://src.fedoraproject.org/rpms/mallard-rng.git /var/lib/mock/f45-build-17981-506/root/chroot_tmpdir/scmroot/mallard-rng
Cloning into '/var/lib/mock/f45-build-17981-506/root/chroot_tmpdir/scmroot/mallard-rng'...
$ git fetch origin 709d80b98298b45991c995ee0a8b1ad9e864b021:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mallard-rng
 * [new ref]         709d80b98298b45991c995ee0a8b1ad9e864b021 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 709d80b Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild