$ git clone -n https://src.fedoraproject.org/rpms/rfcdiff.git /var/lib/mock/f45-build-34505-687/root/chroot_tmpdir/scmroot/rfcdiff
Cloning into '/var/lib/mock/f45-build-34505-687/root/chroot_tmpdir/scmroot/rfcdiff'...
$ git fetch origin f878505cb1da7947cdb7ab63be3539eee16f43f8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rfcdiff
 * [new ref]         f878505cb1da7947cdb7ab63be3539eee16f43f8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f878505 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild