As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SMOKE AFT LAV MASTER WARNING ON DESCENT AT 13000 FT FOLLOWED QRH CHECKLIST AND PULLED ALL NECESSARY BREAKERS. INSPECTED REAR LAVATORY AND FOUND NO SIGNS OR ODORS OF SMOKE. RESET CIRCUIT, BREAKERS AND PERFORMED OPERATIONAL TEST OF AFT LAV SMOKE DETECTOR IAW AMM 26-16-00 NO DEFECTS NOTED AT THIS TIME.