- var_dump: documentation ( source)
<?php
$html = 'abc<br>def';
var_dump(\Dom\HTMLDocument::createFromString($html, options: LIBXML_NOERROR|\Dom\HTML_NO_DEFAULT_NS)->saveHtml());
$dom = new \DOMDocument(encoding: 'UTF-8');
$dom->loadHTML($html, LIBXML_NOERROR| LIBXML_HTML_NODEFDTD);
var_dump($dom->saveHtml());