Sign diagnostic

The structural form of the same diagnostic is XII-D's: at $\gamma =0$, $L{r}_{\mathrm{D}}[K\xi ]=-J_3[K\xi ]=A{s}_{\xi }$, the $L$-image of the X-A slot change $s_{\xi }-K{\rho }_{\xi }$, whereas $L{u}_{\mathrm{D}}[K\xi ]=-A{s}_{\xi }$ is the $L$-image of a slot change no element of ${\mathcal{G}}_U$ produces. The witness value $I$ is cited from XI-E, not recomputed.