Why does Grails need Xerces?

We had in a grails-project problems with different XML-libraries clashing. The solution was to delete xercesImpl.jar from $GRAILS_HOME/lib. Grails does work well without it. So my question is, why was the xerces-library in the grails-distribution in the first place?

From stackoverflow Mnementh

• A common reason for including an XML parser is if the application needs to run on earlier JRE versions.

  Mnementh : +1 That sounds reasonable.
  From Joachim Sauer