Examine source code of EventSentinel

{
  "manifest_version": 3,
  "name": "EventSentinel",
  "version": "1.0.0",
  "description": "Audit inline DOM event handlers and javascript: URLs on the active page.",
  "icons": {
    "48": "badge/icon-48.png",
    "96": "badge/icon-96.png",
    "128": "badge/icon-128.png"
  },
  "action": {
    "default_title": "EventSentinel",
    "default_popup": "panel/view.html",
    "default_icon": {
      "48": "badge/icon-48.png"
    }
  },
  "permissions": [
    "activeTab",
    "scripting",
    "clipboardWrite"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a75ea471-53ed-4291-a382-e20acfe96d4e}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}