Examine source code of Super Snow

{
  "name": "Super Snow",
  "version": "0.0.0.1",
  "manifest_version": 2,
  "description": "Improve privacy of applications by defending shoulder surfing",
  "homepage_url": "http://sechow.com/snow",
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "background": {
    "scripts": [
      "js/background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_icon": "icons/icon128.png"
  },
  "permissions": [
    "<all_urls>",
    "activeTab"
  ]
}