As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BURNING SMELL, LIKE FIREWORKS, DURING CRUISE AND INTO DESCENT. PERFORMED FIM. FOUND PACK 2 EXHAUST GRATE AND DUCT TO BE AT FAULT. REMOVED AND REPLACED PACK 2 EXHAUST GRATE AND DUCT. OPS CHECK GOOD AT THIS TIME. NO FURTHER DEFECTS NOTED. NO BURNING SMELL NOTED.