Examine source code of Peacock

{
  "theme": {
    "images": {
      "theme_frame": "Persona_Header_Peacock.jpg"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000"
    }
  },
  "version": "2.0",
  "name": "Peacock",
  "manifest_version": 2,
  "description": "Closeup of peacock feathers.\n<a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/0a648649ce057dde3fb6a3811f89ad1248a51864309d4467d9420a661c671e32/http%3A//www.istockphoto.com/mittymatty\">http://www.istockphoto.com/mittymatty</a>"
}