As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI, THE FLIGHT ATTENDANT SAW AND SMELLED SMOKE COMING FROM THE AFT INSIDE CABIN OUT OF THE FLOOR VENTS. THE CREW DECLARED A GROUND EMERGENCY. MX WAS CALLED AND FOUND THE RIGHT PACK HAD OVERTEMPED. MX PLACED IT ON MEL. MX PERFORMED ENGINE RUNS. MX REPLACED FAN BY-PASS CHECK VALVE NO FURTHER DISCREPANCIES FOUND.