<?php
$dom = new DOMDocument();
$dom->loadHTML('<?xml version="1.0" encoding="UTF-8"?>'.'<h2>asdf</h2>');
$header_nodes = (new DOMXPath($dom))->query('//*[self::h2 or self::h3]');
var_dump($header_nodes->length);
Warning: PHP Startup: Unable to load dynamic library 'sodium.so' (tried: /usr/lib/php/8.3.5/modules/sodium.so (libsodium.so.23: cannot open shared object file: No such file or directory), /usr/lib/php/8.3.5/modules/sodium.so.so (/usr/lib/php/8.3.5/modules/sodium.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
int(1)