`request-partial-message-method' is required to return structure of
message at current summary line. Format of it is mime-entity.
+
+** User-Agent field
+
+ MIME-Edit inserts User-Agent field instaed of X-Emacs field if
+`mime-edit-insert-user-agent-field' is not nil. Contents of
+User-Agent is specified by mime-edit-user-agent-value'.
+
+ X-Emacs related features were abolished.
+
\f
* Changes in SEMI 1.7