Examine source code of Abstract Blue - Harmony

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000"
    }
  },
  "version": "2.0",
  "name": "Abstract Blue - Harmony",
  "manifest_version": 2,
  "description": "Cool abstract looking theme, for Firefox.\n\nImage source: <a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/36b123939e7732919a4803256aa2e1786384ae92e77040cb1ff6555b839f95fb/http%3A//wall.alphacoders.com/index.php%3Fs=abstract\">http://wall.alphacoders.com/index.php?s=abstract</a>"
}