The benefit is that a DITA-sensitive application can detect DITA content and
determine the architecture version that governs the content by inspecting the
topic or map element that contains the content.
As a footnote, the attribute might be renamed to DITAArchVersion or something
similar so it isn't specific to DTDs.
2. In DITA 1.0, the OASIS TC will define a namespace for each vocabulary or
document type shell and, for each shell, provide both a namespace-free DTD or
Schema shell and a namespaced wrapper around that namespace-free shell. The
OASIS TC will mandate this design pattern for all shells.
The benefit is that a DITA-insensitive application that requires namespaces
can recognize a specific DITA vocabulary based on its namespace. DITA adopters
who don't require namespaces don't have to use them.
3. The OASIS TC will note that, in a future version of DITA, each
specialization module _may_ be identified by namespace. That implications and
implementation of that strategy require more investigation after DITA 1.0
In conclusion, I'd like to thank the participants in these discussions for
their determination and insight.