As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
VISIBLE SMOKE WITH ODOR OF BURNING RUBBER IN CABIN AT FL 390. TURNED OFF RECIRC FANS, ODOR AND SMOKE DISSIPATED, DURING DESCENT AND LANDING. FOUND RT HYD SYS RESERVOIR OVERFULL. DRAINED TO PROPER LEVEL. NO OTHER DISCREPANCIES FOUND. NO ODOR OR SMELL USING ACFT PACKS AT GATE.