Examine source code of The Firefox Minimalist

{
  "theme": {
    "images": {
      "theme_frame": "firefox_minimalistic.png"
    },
    "colors": {
      "frame": "#c0c0c0",
      "tab_background_text": "#f2f2f2"
    }
  },
  "version": "2.0",
  "name": "The Firefox Minimalist",
  "manifest_version": 2,
  "description": "Simple and clean."
}