As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED STRONG BURNING ODOR IN THE FLIGHT DECK & FWD PAX CABIN WITH NO SMOKE PRESENT WHILE EN ROUTE. AN EMERGENCY WAS DECLARED & AN UNSCHEDULED LANDING WAS SUCCESSFULLY PERFORMED. FOUND THE OVERHEAD LIGHTING ABOVE ROWS ONE & TWO WAS FOUND TO BE INOPERATIVE. THE ROW ONE OVERHEAD LIGHT BALLAST WAS REPLACED, NO SMELL REMAINED & ALL OPERATIONAL CHECKS WERE GOOD.