The XYZ To UVW map is also known as planar projection or flat mapping. This Projection map takes the coordinates in world or object space and use them as UVW coordinates. For images, only the X and Y coordinates are relevant, which are mapped to U and V. In other words, the images project flat mapping along the Z axis.
Rotating the mapping around the Z axis rotates the image around the center, as the UVW rotation would do.
Figure 1: XYZ To UVW map