List Flag: filter-mime

Removes MIME blocks from submissions, except those blocks whose Content-Type
is "TEXT/PLAIN".  In other words, it attempts to filter out attachments to
mail messages which contain anything other than plain, readable text.

The start of a filtered block is determined by a line which:
	(a) contains "--" followed by the MIME boundary as specified by a
	    Content-Type: header; and
	(b) is followed by a line which starts with something other than
	    "Content-Type: text/plain"

All text following that point in the body of a message is omitted.

NOTE: This flag is obsolete and is being replaced by the "mime" command.