This is the regular expressions configuration which validates for HTML. For more information, see <a href="https://www.php.net/manual/en/reference.pcre.pattern.syntax.php " target="_blank" rel="noopener noreferrer">here</a>.
<b>Warning:</b> This is an important setting. Select a wrong option here can break the site or affect some features. If you are unsure about which option to configure, use the default value or contact us for support.