As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAXI OUT PILOTS & ALL FA'S NOTICED STRONG "ELECTRICAL" TYPE OF SMELL. SOURCE UNIDENTIFIED, RAN THE SMOKE, FIRE, FUMES CHECKLIST AND WERE UNABLE TO DISCOVER SOURCE. RETURNED TO GATE. FOUND IDG NR 2 FEEDER CABLE DAMAGED IN CARGO AND REPLACED CABLE.