Support of the remainder

Compare XI-E's support formula for arbitrary compact ghosts, which had the additional layer $\{0\le t\le \epsilon \}$: an unrestricted ghost can enter the ramp, while the de Donder parameter selected by the cubic response cannot, because it is retarded from $U$. The remainder is a genuine switching defect: for an observation whose dependence region meets $\mathrm{supp}\mathrm{d}g$ inside $J^{+}(\mathrm{supp}\xi )$, the second-order parameter forced by gauge fixing reaches the switching region, where the switched scalar action is not covariant. It is zero on the witness and under (eq:plateauzero).