Plan 9 from Bell Labs’s /usr/web/sources/contrib/fernan/nhc98/src/libraries/HaXml/tests/xml-conformance/ibm/xml-1.1/not-wf/P02/ibm02n28.xml
<?xml version="1.1" encoding="UTF-8"?> <!-- Bad Comment 0x1c --> <?Bad PI 0x1c ?> <root><![CDATA[ 0x1c ]]></root>