Clarification on /wstop:Topic/@messageTypes attribute

["Vambenepe, William N" <vbp@hp.com>]

WS-Topics says (in section 6 "Modeling topics in XML"):

/wstop:Topic/@messageTypes
An optional list of the QNames of XML elements that define the types of
NotificationMessage that may be used with the Topic. A Publisher using a
given Topic MUST NOT generate a NotificationMessage whose type is not
included in this list, although the special value xsd:any indicates that
any NotificationMessage type MAY be used. A given QName MAY appear
multiple times in the list; second or subsequent appearance of a given
QName are not meaningful and MAY BE ignored. If this list is empty, or
the attribute not defined, the default value of "xsd:any" is assumed. 

Does this mean that the value of the @messageTypes attribute is a list
of complex types or elements? The text looks very confusing the me. I
think it should be "element" if only because it makes it a lot easier to
know which one you are receiving (since a type won't give you the name
of the top level element). But if that's the case, the word "type"
appears in way too many places in this text, including the very name of
the attribute.

What do the rest of you understand from this?

William