Examine source code of Worlds

{
  "theme": {
    "images": {
      "theme_frame": "TopWorlds.jpg"
    },
    "colors": {
      "frame": "#cfc9c9",
      "tab_background_text": "#f2e9e9"
    }
  },
  "version": "2.0",
  "name": "Worlds",
  "manifest_version": 2,
  "description": "I hope you like it!"
}