QueryPath is a PHP library for manipulating XML and HTML. It is designed to work not only with local files, but also with web services and database resources.
You're right. If you have a minute to issue a pull request, that'd be great. Otherwise, I'm a little stalled on QueryPath work and probably won't get to it until next week.
Using more or less the pattern documented on the homepage:
It looks like the class needs to be whitelisted here: https://github.com/technosophos/querypath/blob/6c677d0158a85ea4632073b19502db92a91c3243/src/QueryPath/DOMQuery.php#L120