Plan 9 from Bell Labs’s /usr/web/sources/contrib/fernan/nhc98/src/libraries/HaXml/tests/xml-conformance/ibm/not-wf/P63/ibm63n01.dtd
<?xml version="1.0" encoding='UTF-8'?> <!-- DTD for Production 63--> <![ignore[ ]]> <!--Negative test with pattern1 of P63--> <!--Case sensitive. ignore is used instead of IGNORE -->