The new areas are a file that shows that the creators are working on new areas. The file was found by SirGawain8. It was believed that one of them was a moon, and another was a waterpark. (Waterpark is not on the photo).
It was later confirmed that there will be a desert area, jungle area, and secret cave area sometime in the future. But some people wonder what's going to happen to the other new areas like the farm, or the moon. The Moon area might have been for the first Ready Jet Go! Event. Only the desert, jungle, and secret cave have been confirmed via the Kart Kingdom Blog so far.In the concept art shown here, it shows the names of some areas: Bug Garden, Farm/Plains, and the Moon.
Some people are upset Kart Kingdom isn't getting a waterpark area.