As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AUS) APU FIRE WARNING LIGHT ILLUMINATED. FIRE BOTTLE DISCHARGED AND WARNING LIGHT EXTINGUISHED. SEVERAL MINUTES LATER, THE WARNING LIGHT ACTIVATED AGAIN AND INTERMITTENTLY ACTIVATED FOR THE REMAINDER OF THE FLIGHT. INVESTIGATION COULD FIND NO CAUSE FOR THE WARNING LIGHT ACTIVATION.