Examine source code of Firedude

{
  "theme": {
    "images": {
      "theme_frame": "FirefoxX.jpg"
    },
    "colors": {
      "frame": "#9d0db3",
      "tab_background_text": "#15c7d4"
    }
  },
  "version": "2.0",
  "name": "Firedude",
  "manifest_version": 2
}