Examine source code of fade away to red

{
  "theme": {
    "images": {
      "theme_frame": "gradual-overdrive-header.jpg"
    },
    "colors": {
      "frame": "#000000",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "fade away to red",
  "manifest_version": 2,
  "description": "just having fun with gradients. . .\n\n<a rel=\"nofollow\" href=\"https://outgoing.prod.mozaws.net/v1/ac47814aa85e488ca98930e9f4c5ab209e38ee12b61ea865f8cca5fba061fcab/http%3A//www.tonyabetz.org/TBG/tbghome.htm\">http://www.tonyabetz.org/TBG/tbghome.htm</a>"
}