Examine source code of Window on Earth

{
  "manifest_version": 2,
  "name": "Window on Earth",
  "short_name": "Window on Earth",
  "version": "1.0.3resigned1",
  "applications": {
    "gecko": {
      "id": "{ed9a235f-fd6d-48c2-aaca-bd4ac1e4158a}",
      "strict_min_version": "60.0"
    }
  },
  "description": "This is a theme featuring views of earth taken from space moving past the window of the ISS. At sunset and sunrise the views change from night to day, and day to night. The browser theme moves correspondingly from dark to lighter.",
  "icons": {
    "64": "icon.png",
    "128": "icon2x.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  },
  "permissions": [
    "theme",
    "alarms",
    "storage"
  ],
  "developer": {
    "name": "Jim Hawkridge",
    "url": "http://jim.hawkridges.co.uk/"
  }
}