As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PUSHBACK CABIN FILLED WITH BURNING SMELL FOLLOWED BY AN APU SHUTDOWN. CAPTAIN OBSERVED A STRONG ODOR OF ELEC BURNING SMELL. INSPECTION ACCOMPLISHED IAW JC 26L00021001 & 26L00021002. ODOR COULD NOT BE DUPLICATED & THERE WAS NO PREVIOUS 30 DAY HISTORY.