DTD's

In DOM-Level1, it was said that the manipulation of DTDs should be
investigated
and could be an addition in DOM Level2. This functionality is, I think,
really needed
and reading the current work done on DOM-Level2, I didn't see anything
in this
direction.
Are there some standardization work done on DTD manipulation ? If yes
can you
tell me where ?

Thanks in advance for you answer.

Willy Picard