As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: AT CRUISE 3L LAVATORY SMOKE ALARMS ALERTED WITH CHIMES AND ENGINE INDICATING AND CREW ALERTING SYSTEM. LAVATORY INSPECTED WITH NO SMOKE DETECTED. ACCOMPLISHED FIM 26-10-F3-42A-421A-A ON 3L LAVATORY OPERATIONS CHECKS OK.