 An 
 implementation dependent warning that may be raised if the configuration 
 parameter "<a href='http://www.w3.org/TR/DOM-Level-3-Core/core.html#parameter-namespaces'>
 namespaces</a>" is set to <code>true</code> and an unbound namespace prefix is 
 encountered in an entity's replacement text. Raising this warning is not 
 enforced since some existing parsers may not recognize unbound namespace 
 prefixes in the replacement text of entities. </dd>
 <dt>
 <code>"unknown-character-denormalization" [fatal]