As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA - FIRST TWO ROWS OF PASSENGERS, AND FLIGHT ATTENDANT, SMELLED AN ODOR OF "BURNING ELECTRICAL" ON DESCENT INTO SEATTLE. NO SMOKE PRESENT. GROUND RAN BOTH ENGINES WITH BLEEDS ON. INSPECTED THOROUGHLY FOR SOURCE OF REPORTED SMELL/ODOR. COULD NOT DUPLICATE. NO DISCREPANCIES NOTED. AIRCRAFT RETURNED TO SERVICE.