I would like a small definition panel attached to each dashboard metric. It would explain the calculation, exclusions, data freshness, and responsible owner without requiring users to leave the dashboard. A link could open the fuller glossary entry for anyone who needs the details.
The panel should also show when a definition changed so readers can interpret a sudden shift in a trend. Success would mean fewer repeated clarification questions and fewer conflicting interpretations of the same chart. Which fields would you make essential, and which would you keep optional?