Situation: required footers are absent in refs where tooling expects them to be.

Complexity: git commits are immutable by design. To add missing metadata to existing commits requires essentially removing them and writing new commits, aka "history rewriting" in git. This rewriting may confuse downstream git users, who may have based their work off removed commits.

Document:
 * what trooper should do to recover from a problem
 * what to tell developers
 * whether to worry about CI/CQ.

Motivation, http://requiem/doc/postmortem103738