$ git clone -n https://src.fedoraproject.org/rpms/sushi.git /var/lib/mock/f40-build-2719262-73001/root/chroot_tmpdir/scmroot/sushi
Cloning into '/var/lib/mock/f40-build-2719262-73001/root/chroot_tmpdir/scmroot/sushi'...
$ git fetch origin 5445102faf4f3f89edfae6a3daf662ff333eb3a3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/sushi
 * [new ref]         5445102faf4f3f89edfae6a3daf662ff333eb3a3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5445102 Update to 46.0