Not all of that information is related to rewards, either. A fan favorite may be making a return: the birthday bus. This special skin for the battle bus wraps it in party streamers and birthday attire, and leaks suggest it will be doing the rounds this year also.
Leaker Mang0e on Twitter found files for both the Battle Bus as well as this year's cakes. As you might expect, a "4" candle will be mounted on top of the birthday bus this year. The cake will probably be found around the map, but also in a special party area. FortTory on Twitter found the birthday bash area for this year's celebration — without the area's flooring. It's unclear whether this party zone will be overlaid on an existing location or a new one.