- Why does the resolution here differ from my display settings?
- Because of display scaling. At 150 percent scaling a 3840 by 2160 screen reports 2560 by 1440, since that is the space software actually lays out in. The physical pixels line gives the number your settings show.
- Why is the window smaller than the screen?
- The window excludes everything outside the page: the browser toolbar, the taskbar, scrollbars and any sidebar. It is the number that matters for a web design; the screen resolution is the number that matters for a wallpaper.
- Can you see this information about me?
- No. The values are read in your browser and rendered on your screen. The page has no server to send them to, which is worth saying because most pages that show this list do collect it.
- Why is memory or graphics missing?
- Both are optional. Firefox and Safari report memory not at all, and browsers with fingerprinting protection often mask the graphics card. Missing here means withheld by the browser rather than absent from the machine.