What are displaySizeMax() and displaySizeMin()?

I’m looking at the methods of Z.ScreenSizeConstrain, but I don’t understand what displaySizeMax() and displaySizeMin() are exactly. Are those the pixel dimensions of the device’s screen?

My aim is to get a plane to cover the screen regardless of its orientation. I’m attempting to get the aspect ratio of the device’s screen so that I can scale the plane accordingly. Is there a better way?

I don’t think it matters. ScreenSizeConstrain doesn’t work at published projects at all anyway. It is working only in studio…