Examine source code of Future King

{
  "theme": {
    "images": {
      "theme_frame": "FirefoxPersona-FutureKingHEADER.jpg"
    },
    "colors": {
      "frame": "#000000",
      "tab_background_text": "#e0e3ca"
    }
  },
  "version": "2.0",
  "name": "Future King",
  "manifest_version": 2
}