As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GOT AN AFT CARGO SMOKE ANNUNCIATION WARNING. DISCHARGED AGENT AND RETURNED TO GATE. FIRE BOTTLE WAS REPLACED. UPON FURTHER INVESTIGATION NO SPECIFIC CAUSE COULD BE IDENTIFIED. SYSTEM OPERATIONALLY CHECKED NORMAL WITH NO FURTHER OCCURRENCES.