As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT MLG LANDING GEAR EXTENSION: PERFORMED EMERGENCY LANDING GEAR EXTENSION DUE TO NO HYDRAULIC FLUID. HYD LOW LVL AND BOTH HYD LOW FLO ANNUCIATORS ILLUMINATED AT FL400. AFTER LANDING, AIRPORT PERSONNEL DISCOVERED HYDRAULIC POOLING AREAS INSIDE THE HYDRAULIC ACCESS PANEL AND INSIDE THE REAR HELL HOLE COMPARTMENT BELOW THE J BOX. THE HYDRAULIC QUANTITY INDICATOR WAS EMPTY AT THIS POINT.