As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING ACFT PUSHBACK, PILOTS REPORTED SMOKE IN THE CABIN ACCOMPANIED BY RT PACK TEMP CAUTION MESSAGE POSTED ON THE EICAS, RT PACK COMPRESSOR DISCHARGE OVERHEAT. ACFT RETURNED TO GATE. NO TIME FOR T/S, HIL/DDG ITEMS WERE OPENED FOR THE RT PACK AND THE ACFT WAS DECLARED SERVICEABLE.