Examine source code of CropmarksStudio.com

{
  "theme": {
    "images": {
      "theme_frame": "firefox-03.jpg"
    },
    "colors": {
      "frame": "#424242",
      "tab_background_text": "#030303"
    }
  },
  "version": "2.0",
  "name": "CropmarksStudio.com",
  "manifest_version": 2,
  "description": "Cropmarks Studio Theme. Special Note: To achieve the best look, go to View - Toolbar - Bookmark Toolbar Enjoy"
}