Examine source code of Word Counter

{
  "manifest_version": 2,
  "name": "Word Counter",
  "version": "1.0",
  "description": "Count words, characters, sentences, and estimate reading time for any text",
  "permissions": [
    "clipboardWrite"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Word Counter"
  },
  "icons": {
    "48": "icon.png"
  },
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "browser_specific_settings": {
    "gecko": {
      "id": "{d00ae9af-8608-43e0-9ceb-ffcc840e41db}"
    }
  }
}