Examine source code of Delete Cookies

{
  "manifest_version": 2,
  "name": "Delete cookies",
  "version": "1.0",
  "description": "Delete all cookies from the active tab directly from the browser toolbar.",
  "icons": {
    "16": "icons/16.png",
    "24": "icons/24.png",
    "32": "icons/32.png",
    "64": "icons/64.png",
    "128": "icons/128.png",
    "256": "icons/256.png",
    "512": "icons/512.png"
  },
  "background": {
    "page": "lib/chrome/background.html"
  },
  "permissions": [
    "tabs",
    "storage",
    "<all_urls>",
    "cookies",
    "notifications"
  ],
  "browser_action": {
    "default_icon": {
      "64": "icons/64.png"
    },
    "default_title": "Delete cookies"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b263cfba-c530-4345-a828-48df309e12a1}"
    }
  }
}