As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED. LAVATORY SMOKE DETECTOR ALARM ILLUMINATED. FLIGHT ATTENDANTS CONFIRMED NO SMOKE IN ANY LAVATORY. LIGHT WENT OUT AT GATE AFTER ENGINE SHUTDOWN. PERFORMED LAVATORY SMOKE DETECTION SELF TEST PER AMM 26-14-00. OPERATIONAL CHECK GOOD.