$ git clone -n https://src.fedoraproject.org/rpms/xmppc.git /var/lib/mock/f45-build-38981-731/root/chroot_tmpdir/scmroot/xmppc
Cloning into '/var/lib/mock/f45-build-38981-731/root/chroot_tmpdir/scmroot/xmppc'...
$ git fetch origin e42c97f0c714e543cbe0657ffe47e5f32ba6220a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xmppc
 * [new ref]         e42c97f0c714e543cbe0657ffe47e5f32ba6220a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e42c97f Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild