2.2.12 [W3C-XSLT] Section 11.2, Values of Variables and Parameters
It is an error if a member of the sequence of nodes created by instantiating the template is an attribute node or a namespace node, since a root node cannot have an attribute node or a namespace node as a child. An XSLT processor may signal the error; if it does not signal the error, it must recover by not adding the attribute node or namespace node.
MSXML3 and MSXML6
No attribute node or namespace node is added.