WordPress Version: 5.9
/**
* Adds `rel="nofollow ugc"` string to all HTML A elements in content.
*
* @since 5.3.0
*
* @param string $text Content that may contain HTML A elements.
* @return string Converted content.
*/
function wp_rel_ugc($text)
{
// This is a pre-save filter, so text is already escaped.
$text = stripslashes($text);
$text = preg_replace_callback('|<a (.+?)>|i', static function ($matches) {
return wp_rel_callback($matches, 'nofollow ugc');
}, $text);
return wp_slash($text);
}