Examine source code of Modern Fox - Colour

{
  "theme": {
    "images": {
      "theme_frame": "Modern-Fox-Header.png"
    },
    "colors": {
      "frame": "#c9c9c9",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Modern Fox - Colour",
  "manifest_version": 2,
  "description": "This is the colour version. A simple design that looks modern and shows off your support for Firefox."
}