As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON ARRIVAL, CREW DECLARED AMBER DUE TO HYDRAULIC SYSTEM QUANTITY AT ZERO. IN LEFT MAIN LANDING GEAR WHEEL-WELL, FOUND FORWARD INBOARD BULKHEAD GREEN SYSTEM B-NUT LOOSE. TIGHTENED IN 1.5 TURNS. SERVICED GREEN SYSTEM, AND PRESSURIZED GREEN SYSTEM BY PTU AND FOUND NO LEAKS. OPS CHECKED GEAR DOORS AND NR 1 REVERSER, NO LEAKS FOUND. SOME EVIDENCE OF HYDRAULIC FLUID FOUND ON OUTBOARD SIDE NR 1 PYLON. THIS WAS DOCUMENTED IN HISTORY.