Examine source code of Red Bubbles

{
  "theme": {
    "images": {
      "theme_frame": "redbubbles.jpg"
    },
    "colors": {
      "frame": "#910000",
      "tab_background_text": "#ffeded"
    }
  },
  "version": "2.0",
  "name": "Red Bubbles",
  "manifest_version": 2,
  "description": "red bubbles on black"
}