Examine source code of Check Page Performance

{
  "manifest_version": 2,
  "name": "Check Page Performance",
  "version": "2.1.9",
  "description": "Detects performance issues like long tasks and low FPS.",
  "permissions": [
    "tabs",
    "notifications"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icons/64.png"
  },
  "icons": {
    "64": "icons/64.png",
    "128": "icons/128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d1825145-2b97-473c-9bff-facece6ed3cf}",
      "strict_min_version": "64.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}