Удалить index из URL ресурсов, дочерних главной

<?php
switch ($modx->event->name) {
    case 'OnWebPagePrerender':
        $modx->resource->_output = str_replace('"index/', '"', $modx->resource->_output);
        break;
    case 'OnPageNotFound':
        $uri = explode('?', $_SERVER['REQUEST_URI']);
        if ($res = $modx->findResource('index' . $uri[0])) {
            $modx->sendForward($res);
        }
        break;
    case 'OnHandleRequest':
        if (strpos($_SERVER['REQUEST_URI'], 'index/') !== false) {
            $url = str_replace('index/', '', $_SERVER['REQUEST_URI']);
            $modx->sendRedirect($url, array('responseCode' => 'HTTP/1.1 301 Moved Permanently'));
        }
        break;
    default:
        break;
}
return;

Взято тут: https://ilyaut.ru/cheats/to-remove-index-from-url-resources-a-subsidiary-of-the-main/