The only thing a HTTP/1.0 client can do with "application/binary"
(which, for the record, isn't even a proper MIME type) is offer to
save it to a file. HTTP/1.0 clients will not look at file extensions
when communicating with HTTP/1.0 servers -- the MIME type returned by
the server will be considered the definitive type.
Sooooooooo, if you want your server to continue to serve multimedia
data elements to Mosaic for X 2.0 and all the other neat HTTP/1.0
clients that will be coming out Real Soon Now and you are running a
server that talks HTTP/1.0 to HTTP/1.0 clients, you should look into
this very soon...
Cheers,
Marc