XMLNS DTD support
The input XML might contain an inline DTD.
Parsing
If the input XML document has an inline DTD, the XMLNS parser reads and uses information in the DTD while parsing, and adds the DTD information to the message tree.
Internal entity definitions in the DTD are used to automatically expand entity references that are encountered in the body of the document.
Attributes that are missing from the input document are automatically supplied with the default value specified in the DTD.
Writing
The XMLNS parser can produce any inline DTD that has been constructed in the message tree.
External DTDs
No support is offered for external DTDs