Illustrator opacity rendering on artboard vs. white objects

I recently stumbled on something curious: the white of the artboard and the white of white objects in Illustrator act quite vastly differently on translucent objects on top of them. For example, this is a 30% black square partially eclipsing a 100% opacity white square on the bottom right corner (boundaries shown by the red markers, the rest is artboard):

Although an intruiging and sometimes helpful feature, I am also concerned about how this will affect my ability to the judge colour and tone of exported translucent images. I am also assuming the lighter tone is a more accurate representation of the final output? What is this feature called, and can I toggle it?