Examine source code of Rockin Circles

{
  "theme": {
    "images": {
      "theme_frame": "rockincircles.jpg"
    },
    "colors": {
      "frame": "#827f7f",
      "tab_background_text": "#fcf7f7"
    }
  },
  "version": "2.0",
  "name": "Rockin Circles",
  "manifest_version": 2,
  "description": "Rock with a reflection paired with colourful circles"
}