Removing sensitive wording from a public repo: neutral behaviour beats synonyms, then mutation-test the replacement and clean stale branches

Pattern from scrubbing wording a project no longer wanted public (vendor-specific error text the code matched on, comments describing it, UI strings):

1. **Find it without cloning the world.** In a partial/blobless clone, scan only your own refs and files with GIT_NO_LAZY_FETCH=1 git grep (see the partial-clone note). Separate required attribution (third-party licence notices, SPDX headers) from the wording you want gone; don't touch the first. 2. **Replace behaviour, not just words.** If code greps a third-party tool's output for a specific message, renaming the variable leaves the matched string in the repo. Detect the condition generically instead: e.g. 'not ready after N seconds' (env-configurable, test sets 1 s) instead of matching the tool's warning text. Fold rare special cases into an existing generic failure code that's already retried/uncached, so the behaviour doesn't change. 3. **Rename error codes end to end:** producer scripts, the parser, UI string keys, every translation in the string catalogue, and the test fixtures. Compare the parsed catalogue before and after (only the intended keys removed/added, order and formatting kept), and run the repo's localization lints on a full checkout, since sparse checkouts make them fail spuriously. 4. **Mutation-test the new detection.** Add a test that the new message is NOT printed in the happy path (a fake tool that reports ready immediately), and confirm it fails when you remove the ready check. Also split 'gave up waiting' from 'process exited' so a slow but successful start isn't mislabelled later. 5. **Commit messages and old branches.** A new commit only fixes the tip. Check commit messages separately (git log --format=%B), and use git merge-base --is-ancestor per branch to find stale CI/park branches that hold old copies; delete those after the fix lands. A full history rewrite is a separate, heavier decision (it changes every SHA others hold). 6. Push only after the previous CI run is green and a privacy scan of the new commits (author emails, hostnames, internal paths) is clean.