B777-200 Captain reported a main wheel fire was reported by ground personnel. ARFF extinguished the fire and maintenance was notified.

Narrative

After landing in ZZZZ on Runway XX we taxied to Gate XX. It was an uneventful landing and a relatively short taxi. We exited the runway at XY and we were told to taxi [Taxiway] XZ XA to Gate XX. After engine shutdown and completing both the Shutdown and Secure Checklists all four pilots were standing in business class waiting for the last few passengers to exit the aircraft. At this point Ground Personnel verbally informed us of a brake fire on the right side truck assembly. None of the Pilots were aware of this problem. The operating FO (First Officer) went to the Cockpit and the Captain; Relief Pilot and Maintenance proceeded to the ramp. When the three pilots arrived by the right side gear we noticed numerous Ground Personnel and Firemen. It appeared that the incident was over because the Foam had already been applied to the Truck assembly. The head Fireman told us it was the front part of the gear which equates to wheels #3 and #4 and that the temperature was now 400C. At least 5-6 Ground Personnel told us they only saw Smoke and no Fire and an equally number of different personnel told us they saw Flames. There didn't appear to be any damage to the airplane; gear doors; gear struts and the other tires. The FO who remained in the cockpit said the brake temperatures never got above 4.6 and that was brake #7. The other 5 temperatures on the right side were considerably lower. We didn't see any Company Maintenance personnel at the time. We later realized that another Air Carrier handled our maintenance operations in ZZZZ and Name was the only one working. So we made an AML entry describing what happened to the Gear and told Company Operations about the write up. The Captain called Company Maintenance in ZZZ after the incident but they already knew about the situation. The Chief Pilot from ZZZ1 also called us.The brake assembly of wheels #3 and #4 were recently replaced. We don't know if this played a part in the fire. Also ZZZ1 ramp had a lot of De Ice fluid and salt around Gate XY. We were wondering if this got caught up in the brakes and once the brakes were 'warmed up' after landing in ZZZZ this might have contributed to the fire.There is not any procedure or action that would have prevented this incident.