As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW INFLIGHT T1680/12 NOV - NUMBER ONE ENGINE LOOP B FIRE WARNING INDICATION. LIGHT WENT OUT AFTER LOWERING THROTTLE ON ENGINE. RETURNED TO DFW AND LANDED WITHOUT INCIDENT. REPLACED BLOWN LEFT AFT ENGINE ANTI ICE DUCT. SYSTEM GROUND CHECKED NORMAL OPERATION.