As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
Crew reported a momentary #2 engine fire indication. The aircraft returned to IAH and landed without incident. Maintenance inspected the right engine and found that the air turbine starter had failed causing heat damage to the engine outer bypass duct and lower cowling. Maintenance removed and replaced the #2 engine, #2 air turbine starter, and performed repairs to the right lower cowl.