Examine source code of Mallard

{
  "theme": {
    "images": {
      "theme_frame": "Mallardheader.jpg"
    },
    "colors": {
      "frame": "#081cf7",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Mallard",
  "manifest_version": 2,
  "description": "Mallard - as photographed at the National Railway Museum, York, UK\n\nThis is my logo for Line Studios [<a href=\"https://outgoing.prod.mozaws.net/v1/6be9b939de45e9afa1ab2c7688e661381d4c6c67ea7270393dd7173ec955c3ac/http%3A//www.line-studio.co.uk\" rel=\"nofollow\">www.line-studio.co.uk</a>]"
}