Examine source code of Featherfall

{
  "theme": {
    "images": {
      "theme_frame": "featherfallheader.jpg"
    },
    "colors": {
      "frame": "#ffffff",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Featherfall",
  "manifest_version": 2,
  "description": "Made with feather brush set found here: <a href=\"https://outgoing.prod.mozaws.net/v1/584523aa65784a4f2dff852d0d5af0ba7e80777127f8792892d06327214a1a90/http%3A//risingheart.deviantart.com/art/Feather-Brush-Set-1-157360186\" rel=\"nofollow\">http://risingheart.deviantart.com/art/Feather-Brush-Set-1-157360186</a>\n\nA simple, clean, white-and-grey feather scheme."
}