Neither text/html nor text/plain is necessary - if no Accept: header
line is present they are taken as default values.
One question: how do you want the client to know what is `sensible' for
a specific request? The only way I can think of is the OBNOXIOUS
peeking at the file extension.
The only way the client can optimize this is to avoid redundant
information - like having a long list of accept headers and then '*/*'
without quality factors.
> Because they try not to be broken, and only ask for what is sensible for that
> request rather than sending the same Accept headers with every request. After
> all, if my client has asked for a document, sending text/html is necessary and
> text/plain seems to be conventional but chemical/pdb is probably superfluous.
> I mention the latter because Arena, having read my mailcap, sends that out when
> it asks for html documents, etc.
> > 3) why Netscape never send a field "Accept: application/postscript" even
> >if the user want receive a PostScript document.
> Because it is broken, but up till now that didn't matter much in practice
-- cheers --