{
  "@context": "https://schema.org",
  "@type": "WebPage",
  "name": "Page not found",
  "description": "The page you requested could not be found. The site displayed a 'Page not found' (404) message instead of the course content.",
  "url": "https://example.com/404",
  "publisher": {
    "@type": "Organization",
    "name": "Unknown",
    "url": "https://example.com"
  },
  "mainEntity": {
    "@type": "Thing",
    "name": "404 Error",
    "description": "The requested page could not be found."
  },
  "breadcrumb": {
    "@type": "BreadcrumbList",
    "itemListElement": [
      {
        "@type": "ListItem",
        "position": 1,
        "name": "Page not found",
        "item": "https://example.com/404"
      }
    ]
  },
  "potentialAction": {
    "@type": "ReadAction",
    "target": "https://example.com/404"
  }
}