* doc/misc/emacs-mime.texi (MML Definition): Mention how to
quote MML tags (bug#18881).
but that's not necessary unless the value contains white space. So
@samp{filename=/home/user/#hello$^yes} is perfectly valid.
+If you want to talk about MML in a message, you need a way to
+``quote'' these tags. The way to do that is to include an exclamation
+point after the opening two characters; i. e. @samp{<#!part ...>}.
+
The following parameters have meaning in @acronym{MML}; parameters that have no
meaning are ignored. The @acronym{MML} parameter names are the same as the
@acronym{MIME} parameter names; the things in the parentheses say which