Typo in Mapping DTDs onto Schema?

In xhtml-m12n-schema/schema-framework.html#sec_2.1.4. Mapping DTDs onto 
Schema, the table in Example 3 - ".mix" Group contain 4 classes 
(Heading.class, List.class, Block.class, Misc.class) in the DTD version, 
but only 3 (Heading.class missing) in the Schema version.

Not that I understand this document (yet), but this may look like a 
typographic error?

Sorry I do not give you the URI, I read an offline version. Maybe you'd 
need something like

         <link rel="DC.identifier"
                         type="text/html"
                         href="http://www.w3.org/.../schema-framework.html" />

to tell me what I really am reading   ;o)

Jan Egil Kristiansen
Faeroe Islands