$ git clone -n https://src.fedoraproject.org/rpms/cjs.git /var/lib/mock/f42-build-side-1-3506307-45996/root/chroot_tmpdir/scmroot/cjs
Cloning into '/var/lib/mock/f42-build-side-1-3506307-45996/root/chroot_tmpdir/scmroot/cjs'...
$ git fetch origin 600d22f4fa05c1f830c95d0958980e6c381f24eb:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/cjs
 * [new ref]         600d22f4fa05c1f830c95d0958980e6c381f24eb -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 600d22f Update to 128.0