Examine source code of Falling Holiday Snow

{
  "name": "Falling Snow",
  "version": "0.0.0.2",
  "manifest_version": 2,
  "permissions": [
    "activeTab"
  ],
  "description": "A Chromium extension to make snow fall on any website.",
  "icons": {
    "16": "icons/snow16.png",
    "32": "icons/snow32.png",
    "48": "icons/snow48.png",
    "128": "icons/snow128.png"
  },
  "browser_action": {
    "default_popup": "popup/popup.html"
  }
}