Perhaps we could extend what Mime is using for 'content-type' to a
more general 'resource type'; some kinds of resources are actual files
with a given format, but other things that we want are URLs for
interactive services which will have a type of 'telnet/3270' vs
'telnet/vt220', or multicast audio and video channels.
I was puzzling how to 'type' these things as long as they were
supposed to fit within 'content-type', until I realized that
content-type could be considered just a subset of a more general case.