As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON ARRIVAL TO GATE, FLIGHT CREW NOTICED SMOKE COMING FROM THE LANDING GEAR CONTROL HANDLE OPENING. FIRE EQUIPMENT WAS CALLED OUT. AFTER SHUTDOWN OF ENGINE, APU, AND UTILITY BUSSES, THE SMOKE STOPPED. MAINTENANCE REPLACED THE LEFT LANDING GEAR DOWN ANNUNCIATION AND THE PROXIMITY SWITCH ELECTRONICS UNIT. LANDING GEAR INDICATION NORMAL.