The U and V axes seem roughly correspond to the tint/temperature (green-magenta/blue-amber) axes that you can find in a white balance tool in photo editors and also as an in-camera setting.

Nb. I'd advise against calling the PCA'd space XYZ because that's a well known standard color space: https://en.wikipedia.org/wiki/CIE_1931_color_space#CIE_XYZ_c...