php-8.0.30-src/ext/dom/tests/not_well_formed2.xml

<?xml version="1.0" ?>
<!-- AttValue: " or ' expected -->
<books>
 <book number=nine>
  <title>The Grapes of Wrath</title>
  <author>John Steinbeck</author>
 </book>
 <book>
  <title>The Pearl</title>
  <author>John Steinbeck</author>
 </book>
</books>