X_DOC_MIGRATION_UNSCANNED
Means
no row in wiki/Upgrading.md sends the reader to a single version section, so the rule read nothing
Typical cause
the summary table was restructured or removed. Reported rather than skipped: a rule with no input is a false green, not a pass
Fix
restore the summary table in wiki/Upgrading.md — each row reads the `X.Y.Z` section, in order