SAX and ignorableWhitespace

This is one of those questions that are more for curiousity than anything,
but does anyone have any information on why ignorableWhitespace was included
in ContentHandler as opposed to LexicalHandler? Based on my understanding of
the guidelines used in determining what belongs in the default interfaces
and what belongs in the extension interfaces it seems to fall under the
latter. It is non-imperative lexical information associated with the parse.
Comments?

Best Regards,
Jeff Rafter