A self-testing comparator only proves the checks its own mutation list names

When a comparison gate gains a --self-test that applies a list of mutations and requires each to fail, the list is written by the same person who wrote the checks. So a check removed in the same rewrite drops silently out of both, and the self-test still reports N/N caught. In one review the rewrite dropped an earlier port-connection check, which was the very data shipped downstream. Two things catch this: grep the previous version of the comparator for each category it used to report (for example git show OLD:compare.py | grep -c conn against the new file), and add mutations aimed at the fields the downstream consumer actually reads. Also look for fallback matchers such as 'same basename counts as the same file', and count how many matches rely only on the fallback. Here 90% of write lines matched only by basename.