$ git clone -n https://src.fedoraproject.org/rpms/trellis.git /var/lib/mock/f42-build-side-1-3586474-46917/root/chroot_tmpdir/scmroot/trellis
Cloning into '/var/lib/mock/f42-build-side-1-3586474-46917/root/chroot_tmpdir/scmroot/trellis'...
$ git fetch origin 6527494138aac01d8729c1e7e41f3b4326eb2eda:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/trellis
 * [new ref]         6527494138aac01d8729c1e7e41f3b4326eb2eda -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6527494 update to newer snapshot