Blizzard has been known to be generous with their in game loot boxes. The chances of the loot boxes offering gold and purple tier items is quite high. With the year ending in 2016, Blizzard has decided to be even more generous with their players.
Each player has received 5 lootboxes in their inventory for the event. Blizzard also thanked the players for their tremendous support, passion, and enthusiasm without which Overwatch would not have been a resounding success that it is.