Question about the XML Schema DTD

Hello,

In the DTD for XML Schema, there is a comment just above the definition 
of the attribute element:
<!-- ref not allowed at top level, name iff at top level -->

I don't understand the "name iff at top level" part. A non-toplevel 
attribute with a type (and no ref) should be able to provide a name. Do 
I miss something ?


Thanks.

   Alain



PS: I know the DTD for XML Schema is not normative.