Examine source code of Express Yourself

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    "images": {
      "theme_frame": "HeaderFireFox.png"
    },
    "colors": {
      "frame": "#242424",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Express Yourself",
  "manifest_version": 2,
  "description": "Use it (:"
}