Checks the web manifest for a 512x512 icon and checks to make sure the image is correct.
From most devices, users can create website shortcuts that appear on the homescreen. The web manifest file allows websites to specify the icon that is used for these shortcuts. If a website does not provide an icon, the device may use a blank icon or a screenshot of the website. All websites should have a web manifest file that declares at least two icons. The recommended sizes are 192x192 pixels and 512x512 pixels.
This test will check the manifest file for an icon that is declared to be 512x512 pixels. It will then download this icon and make sure that it is the correct size and file format.