Testing how Googlebot deals with the screen size. This test adds 1,500 divs with a height of 1,000px in 1ms intervals. It also logs the viewport size at the start and monitors for resize events.
A first resize at 5 seconds changed outerWidth from 412 to 1 and outerHeight from 732 to 1 and scale from about 0.4 (it varies) to 1. I'm not sure what is going on there?
A second resize at 5.3 seconds pumps the innerHeight and height from 2,385px to about 1,250,000px. That is one tall viewport!