A source or a note (3 passages, no note) has not changed for longer than the configured threshold (note: Publication threshold). The date (44 passages, no note) comes from git (24 passages, no note) and is always right.
Check (note: Check) W-STALE, severity (note: Severity) warning by default, documented with a before and after example in the check pages. The severity can be overridden per project (note: Project) or per repository (note: Knowledge repository).