Examine source code of Auto Cookie Expiry

{
  "manifest_version": 2,
  "name": "Auto Cookie Expiry",
  "description": "Automatically remove cookies whose expiration date has passed, preserving current ones",
  "version": "1.0",
  "icons": {
    "64": "64.png"
  },
  "permissions": [
    "cookies",
    "storage",
    "alarms",
    "<all_urls>"
  ],
  "browser_action": {
    "default_icon": "64.png",
    "default_title": "Auto Cookie Expiry",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7a9a7513-7be2-4ca4-bdc9-ad7e15b6c997}",
      "strict_min_version": "90.0"
    }
  }
}