Justification in the diff

A rule, ruling, or approval takes effect only where a reviewer will encounter it, which is inside the diff of the change it governs. A reviewer reads a bounded set of removed and added lines and decides on that evidence, so a justification held in a policy file, a decision log, or an untouched region of the working tree is absent at the moment of decision and approves nothing. The placement is structural rather than editorial: it is what makes the reason and the change reach the same reader in the same breath.