apply_filters( 'ms_user_list_site_class', string[] $site_classes, int $site_id, int $network_id, WP_User $user )

392<?php393			 * @param string[] $site_classes Array of class names used within the span tag.394			 *                               Default "site-#" with the site's network ID.395			 * @param int      $site_id      Site ID.396			 * @param int      $network_id   Network ID.397			 * @param WP_User  $user         WP_User object.398			 */399			$site_classes = apply_filters( 'ms_user_list_site_class', $site_classes, $site->userblog_id, $site->site_id, $user );400 401			if ( is_array( $site_classes ) && ! empty( $site_classes ) ) {402				$site_classes = array_map( 'sanitize_html_class', array_unique( $site_classes ) );403				echo '<span class="' . esc_attr( implode( ' ', $site_classes ) ) . '">';404			} else {405				echo '<span>';