> Your screen is 1512 by 982 pixels, rendered at 2x density — which means it is almost certainly a recent, high-end display. Your device volunteered all of this in the first milliseconds of the connection.
No it didn't. It was queried by the JS running on the page. It's a fun demo but it could really do without the slop prose.
Yeah, no need JS to track resolution or even mouse movements with timing, pure HTML/CSS can do.
Pedantic but right. The JS queries them; the browser returns them without prompting the user. "Volunteered" is the editorial verb for that round-trip but it does paper over a layer.