Examine source code of Dark Design Graphics

{
  "theme": {
    "images": {
      "theme_frame": "Firefox-Persona.jpg"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Dark Design Graphics",
  "manifest_version": 2,
  "description": "Persona from <a href=\"https://outgoing.prod.mozaws.net/v1/2b0acb4e5876998eeab60ffafcc9827f2c54d91e9c3d8a2b0eec38b165f5a145/http%3A//darkdesigngraphics.co.uk\" rel=\"nofollow\">darkdesigngraphics.co.uk</a>"
}