Question from the Next.js test

Here is a code snippet from a Next.js application with a dynamic route:

// pages/posts/[id].js
import { useRouter } from 'next/router';

export default function Post() {
  const router = useRouter();
  const { id } = router.query;

  return <div>Post ID: {id}</div>;
}

What is the feature used to handle dynamic routes here?