After a lot of wrangling about how to present form data
within multipart, RFC 1867 ("Form-based File Upload in HTML")
recommended that data returned from filling out a form
be returned as multipart/form-data where each part is
identified with
content-disposition: form-data.
One of the things holding back RFC 1867 from standards track
is that content-disposition was itself "experimental". There is
ample experience now with RFC 1867, at least in HTTP, although
there are some mail implementations as well.
draft-moore-mime-cdisp-00
makes no mention of this use of content-disposition.
This was an accidental omission on my part; I had intended to include
form-data and simply forgot to do so. Barring strong objections, I'll
put it in the next draft.
Keith