Specifies that this property attribute takes an XML value.
<XML/>
None.
Parent: attribute.
Children: None.
This element is one of several you can use to specify the type of a property attribute's value. The complete list includes boolean, class-name, class-names, date, decimal, enumeration, file-path, integer, QNAME, text, URI, URL, URN, XML, or custom. Note that you may use only one of these types for a given attribute.