PEAR::XML_DTD parsing of DTD files and DTD validation of XML files.
The XML validation is done with the php sax parser, the xml extension, it
does not use the domxml extension.

Currently supports most of the current XML spec, including entities,
elements and attributes. Some uncommon parts of the spec may still be
unsupported.

WWW: https://pear.php.net/package/XML_DTD