X_DOC_MIGRATION_UNPAIRED
Means
a BREAKING — line and the Upgrading entry that migrates it do not pair one-to-one
Typical cause
from 23.0.0 on, each BREAKING — line in CHANGELOG.md names its row of that major's Entry by entry table as (#N) straight after the dash. A line with no key, a key named twice or out of order, a key with no row, or a row no line names is a finding: the count rule (X_DOC_MIGRATION_COUNT_STALE) agrees when one line is added on each side for two different changes
Fix
bun run scripts/changelog-check.ts --json — it names the lines; write (#N) after each dash, N the row in wiki/Upgrading.md