$ git clone -n https://src.fedoraproject.org/rpms/unlambda.git /var/lib/mock/f45-build-37725-717/root/chroot_tmpdir/scmroot/unlambda
Cloning into '/var/lib/mock/f45-build-37725-717/root/chroot_tmpdir/scmroot/unlambda'...
$ git fetch origin 4ea8ca83e3a61f5cd0c2688794834ddbd6f1c55d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/unlambda
 * [new ref]         4ea8ca83e3a61f5cd0c2688794834ddbd6f1c55d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4ea8ca8 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild