As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PUSHBACK A LAVATORY SMOKE INDICATION WAS RECEIVED. THE AIRCRAFT RETURNED TO THE GATE AND THE PASSENGERS DEPLANED NORMALLY. THERE WAS NO INDICATION OF SMOKE IN THE LAVATORY. CLEANED THE BACKING PLATE FOR THE LAVATORY LIGHT AND RETURNED THE RETURN TO SEAT LIGHT. PERFORMED AN OPS CHECK FOR 1.5 HOURS WITH NO FURTHER PROBLEMS EXPERIENCED. AIRCRAFT RETURNED TO SERVICE.