More on xs:anySimpleType

Hit the send button a mite too fast on my previous question since I now find the following at http://www.w3.org/TR/xmlschema-1/#section-Built-in-Simple-Type-Definition

There is a simple type definition nearly equivalent to the simple version of the ·ur-type definition· present in every schema by definition. It has the following properties:
      Simple Type Definition of the Ur-Type 
            Property Value 
            {name} anySimpleType 
            {target namespace} http://www.w3.org/2001/XMLSchema 
            {base type definition} ·the ur-type definition· 
            {final} The empty set 
            {variety} ·absent· 
     



But I'm not sure that this entirely answers the question - the words "nearly equivalent" are worrying as the exact impact of the use of the word "nearly "doesn't seem to be fully explained. Again any insight would be helpful.

Thanks

Hugh Wallis