In both the 1E (2001) and 2E (2004) publications of XSDL 1.0 Datatypes,
there is a problem which prevents the proper display of the XML version
of the document in Firefox:  the entity nbsp is referred to, but not
defined in the internal DTD subset.  (Since Firefox and other Mozilla-based
browsers do not consult the external DTD subset, all entities used must be
defined in the internal subset in order for things to work as they should.)

Tests run locally suggest that adding a definition of nbsp suffices to
make both the 2001 and 2004 versions of datatypes.xml, and the 
2004 version of datatypes-with-errata.xml, display correctly in Firefox.

There is no analogous problem in either the Primer or in Structures;
the XML versions of both display fine in Firefox.

Other browsers do not display the formatted XML even with the change
described above:  Opera reports an XSLT processing error because the 
stylesheet uses the document() function, which Opera does not currently 
support.  Safari reports no error, but also displays only a blank window.  
I haven't found an error console in Safari, so I don't know what the problem 
is.  I have not been able to check in Internet Explorer.

We should probably request that 1E and 2E be republished in place, with
the missing entity declaration supplied.  (An entity may also be
missing in compDefs.xml, but I don't have time to track that down just
now.)

For the future, we may wish to consider whether we want to publish the
XML version of the spec in a form that does not require the stylesheet
to use the document() function.