*   <li>Manages crawl delay settings per user agent</li>
 *   <li>Stores sitemap URLs listed in robots.txt</li>
 * </ul>
 *
 * <p>The class uses case-insensitive pattern matching for user agents and supports
 * wildcard characters (*) in user agent strings. When multiple directives match a user agent,
 * the most specific (longest) match is used.</p>
 *
 */
public class RobotsTxt {