Examine source code of Superman Dawn

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000"
    }
  },
  "version": "2.0",
  "name": "Superman Dawn",
  "manifest_version": 2,
  "description": "Made from a wallpaper from <a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/4ec0d59bc4567f216affa948907b585bc8741202f1efcae79dc9008391b20e3b/http%3A//www.supermanhomepage.com/\">Superman Homepage</a>."
}