Examine source code of Cloudy Circles

{
  "theme": {
    "images": {
      "theme_frame": "blurrycir.jpg"
    },
    "colors": {
      "frame": "#3c8aba",
      "tab_background_text": "#44c7c5"
    }
  },
  "version": "2.0",
  "name": "Cloudy Circles",
  "manifest_version": 2,
  "description": "Greenish clouds with beveled circles"
}