X_DOC_UNRELEASED_STALE
Means
a current page calls a version "unreleased" that CHANGELOG.md has dated — or, at a release commit or with [Unreleased] empty, says As of Unreleased, "not yet tagged", what the next major does, or carries a Known-Gaps `main` cell (scripts/doc-unreleased.ts)
Typical cause
33 lines written the day before a major shipped said it was not out yet, were false the day after, and nothing re-read them. changelog-check reads the nearest version within 40 characters of the word, on every page but docs/plans/ and the changelog; a ratchet in scripts/lib/unreleased-claim-pins.ts until the docs sweep lands
Fix
edit the line the finding names — drop "unreleased", or name the version that is — then bun run changelog-check