Examine source code of Rainbow-less Sky

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Rainbow-less Sky",
  "manifest_version": 2,
  "description": "Based on <a rel=\"nofollow\" href=\"https://addons.mozilla.org/firefox/addon/thoughtful-rainbow-dash/\">https://addons.mozilla.org/firefox/addon/thoughtful-rainbow-dash/</a> . I liked this theme, but I sometimes would like to be able to use it in an environment where having a pony on screen would be problematic. Switch to this one when needed."
}