The README says whether the project is maintained
A project that stopped four years ago and one that shipped last week look the same in a search result. Saying which costs a sentence and saves a reader a day.
Observable check
README.md carries a statement of maintenance or support status, or the repository carries an equivalent signal: DEPRECATED as the first heading of README.md, DEPRECATED at the start of the repository description, a no-maintenance-intended badge, or the archived flag set.