Up until now, we have set just one UV layer whose name is, by default, UVMap (go to the Object Data window and look under the UV Maps subpanel):
Actually, in Blender, it is possible to set more than one UV coordinates layer on the same object in order to mix different UV projections that can eventually also be baked into a single image map.
The names of the UV layers under the UV Maps subpanel are important, because they specify which one of the projections a material has to use for the mapping of a texture. By clicking on the + icon to the side of the UV Maps subpanel, it is possible to add a new UV layer (whose name, in this case, will be UVMap.001 by default; of course it's possible to change these names by using Ctrl + clicking on them and typing the new ones).