Examine source code of Google Forms Autofill

{
  "manifest_version": 3,
  "name": "Google Forms Autofill",
  "version": "2.1",
  "description": "Autofill Google Forms using your saved answers",
  "browser_specific_settings": {
    "gecko": {
      "id": "google-forms-autofill@extension",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "icons": {
    "16": "icons/extension_icon.png",
    "32": "icons/extension_icon.png",
    "48": "icons/extension_icon.png",
    "128": "icons/extension_icon.png"
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/extension_icon.png",
      "32": "icons/extension_icon.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://docs.google.com/forms/*",
        "https://docs.google.com/forms/d/*",
        "https://docs.google.com/forms/u/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ]
}