As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SFO - APPROXIMATELY 30 MINUTES PRIOR TO DESCENT, A STRONG SMELL RESEMBLING BURNING INSULATION APPEARED IN THE LOWER GALLEY. AFTER ALL GALLEY POWER REMOVED ODOR DISAPPEARED. FOUND STROBE LIGHT FLASHER UNIT PRODUCING SMELL. PLACED GALLEY POWER ON BUSES 1, 2, 3, NO ODOR NOTED. NO PARTS REPLACED.