Records do not determine residual access

These statements sharpen the source boundary in the notation used here, in agreement with VII-E's accessible-observable and residual-obstruction results CheungVIIE (Proposition prop:accessible and Theorem thm:residual-obstruction). A produced record can become a source only when its surviving register and source algebra are explicitly named. Record agreement alone does not justify using an unnamed residual observable as a source.

No readout or residual-changing instrument occurs in the T0 word constructed below.