Examine source code of Roundcube themes

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#7b81ad",
      "tab_background_text": "#6de8b5"
    }
  },
  "version": "2.0",
  "name": "Roundcube themes",
  "manifest_version": 2,
  "description": "The best <a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/3aa5b524e76155965f14c3116f5c2eb7d7c36f2b72f9cf02035ba1ed15e73e5b/http%3A//webresponsivedesigns.com\">responsive</a> roundcube themes for the world famous browser: <a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/4e0525c5d453f38888d038795271949c4d61dcb84e140d11c47a443f1c2c39c9/https%3A//www.mozilla.org/en-US/firefox/new/\">Mozilla Firefox</a>"
}