As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT AFT LAV SMOKE DETECTOR WENT OFF ON TAKEOFF. PRECAUTIONARY LANDING AT KLGA. INSPECTED A/C OVENS AND VENTILATION SYSTEM. ALSO, INSPECTED TAIL CONE AREA, INCLUDING BOTH PACKS. RAN PACKS, NO SMOKE NOTED. REPLACED BATTERIES IN BOTH AFT LAVS SMOKE DETECTORS AS PRECAUTION.