just have xdebug enabled, see no detailed var_dump
disable xdebug via php.ini and get detailed var_dump
code same as in linked xdebug bug report:

<?php
$DOMDocumentNode = new DOMDocument();
$DOMDocumentNode->loadXML('<example a="b">Test</example>');
$DOMElementNode = $DOMDocumentNode->documentElement;
$DOMAttributeNode = $DOMElementNode->getAttributeNode('a');
$DOMTextNode = $DOMElementNode->firstChild;

var_dump($DOMDocumentNode, $DOMElementNode, $DOMAttributeNode, $DOMTextNode);