[WordPress] Append WordPress Page Content From the Database

00-the-init.php

<?php

public function init() {

	$page_id = get_option( 'acme_display_page_id', 0 );
	if ( 0 === $page_id ) {
		return;
	}

	add_filter( 'the_content', array( $this, 'the_content' ) );
}

02-get-users.php

<?php

private function get_users() {

	$args = array(
		'orderby' => 'ID',
		'role'    => 'Editor',
	);
	$user_query = new \WP_User_Query( $args );

	return $user_query;
}

03-build-the-markup.php

<?php

private function get_user_markup( $user_query ) {

	$content = '';

	if ( 0 === $user_query->get_total() ) {
		return;
	}

	$users = $user_query->get_results();
	$content = '<ul>';
	foreach ( $users as $user ) {

		$login = $user->data->user_login;
		$content .= "<li>$login</li>";
	}
	$content .= '</ul>';

  // Note: Use proper escaping or wp_kses to sanitize this data.
  return $content;
}