Examine source code of Number Ninja

{
  "manifest_version": 3,
  "name": "Number Ninja",
  "version": "1.0",
  "description": "Train your brain with fast mental math challenges. Answer multiple-choice arithmetic questions and improve your calculation speed in this fun popup game.",
  "icons": {
    "48": "ninja_icon.png"
  },
  "action": {
    "default_popup": "index.html",
    "default_title": "Number Ninja"
  },
  "permissions": [],
  "browser_specific_settings": {
    "gecko": {
      "id": "{e12ebd83-6dd7-4c78-84a2-678d914af71e}",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  }
}