Examine source code of Word Counter

{
  "manifest_version": 3,
  "name": "Word Counter",
  "version": "1.0.0",
  "description": "Live word and character counter for text inputs.",
  "browser_specific_settings": {
    "gecko": {
      "id": "wordcounter@local",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "clipboardWrite"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-script.js"
      ],
      "run_at": "document_idle"
    }
  ]
}