Re: [Moderator Action] Missing DTD files

The recommended DTD files for XHTML are missing at W3C. The present  
message contains an examination of the case and suggests a workaround.
Diagnosis:
For the SYSTEM identifier for XHTML 1.0 Transitional as recommended by  
Strictly Conforming Documents the server reply is
Service Unavailable

Content-Location: msie7.asis

Vary: negotiate, User-Agent
And when you try the content location explicitly, you get
Not Found
Therefore, XHTML documents with the recommended DOCTYPE do not  
validate as XML.  This misconfiguration is a severe bug and it may  
cause major disruption to XML applications worldwide.
Workaround:
1.       the links in Document Type Definitions work,
2.       you are free to use any SYSTEM identifier that works,  
although it is not recommended.
Note that all DTDs refer to the invalid location in the usage section.
BTW:
Why are the DTDs served as text/plain?  They should be served as  
application/sgml and application/xml-dtd, as applicable!
HTH,
Chris