Oh! I get it. In the old days, the browser saw an ISINDEX
HTML tag, and that made the "Search Keywords" field activate.
But this could only work for HTML documents. So the idea
is to put the information (that the object is searchable
in such-and-such way) into the object header instead of the
content.
If that's the real and true reason, then the RFC should explain
that.
But my argument about ISMAP still makes sense doesn't it? It's
one thing to "blindly" search a document with text keywords,
it's another to submit a pair of X Y coordinates.
And I certainly see the need for this information now. But
tell me, do the existing browsers check for these methods in
the header? My server certainly is not returning them at present,
and things still work, but perhaps that's because they are not
needed when the data is HTML.