Plan 9 from Bell Labs’s /usr/web/sources/contrib/fernan/nhc98/src/libraries/HaXml/tests/xml-conformance/ibm/not-wf/P63/ibm63n02.dtd
<?xml version="1.0" encoding='UTF-8'?> <!-- DTD for Production 63--> <![[IGNORE[ <!ELEMENT animal EMPTY> <!ELEMENT tiger EMPTY> ]]> <!--Negative test with pattern2 of P63--> <!--Extra '[' is used before IGNORE. -->