Examine source code of Howdy Stranger

{
  "manifest_version": 2,
  "name": "__MSG_extension_title__",
  "version": "1.5",
  "default_locale": "en",
  "description": "__MSG_extension_description__",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "permissions": [
    "activeTab",
    "cookies",
    "<all_urls>",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icons/icon-32.png",
    "default_title": "__MSG_extension_default_text__"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}