$ git clone -n https://src.fedoraproject.org/rpms/golang-github-clbanning-x2j.git /var/lib/mock/f40-build-2253887-54221/root/chroot_tmpdir/scmroot/golang-github-clbanning-x2j
Cloning into '/var/lib/mock/f40-build-2253887-54221/root/chroot_tmpdir/scmroot/golang-github-clbanning-x2j'...
$ git fetch origin 3a20653ba3885777d4a21d9670d8228ef4e6b6fe:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-github-clbanning-x2j
 * [new ref]         3a20653ba3885777d4a21d9670d8228ef4e6b6fe -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3a20653 Remove deprecated %patchN syntax