Device Stage is a set of baked-in icons and menus for printers, cameras, phones, etc. that wait for the moment when you plug something in. Recognition comes fast and smooth—provided the gadget is supported. UPDATE
When you connect a supported gadget, like in this case the Epson Artisan 800, you instantly see the icon with its shiny black case and colorful printout. There was no download, this stuff was already cached somewhere. The icon at first had a yellow alert badge, but after a quick troubleshoot wizard, the badge changed to a happy green check mark.