:type '(repeat (repeat string)))
(defcustom message-mail-user-agent nil
- "Like `mail-user-agent'.
-Except if it is nil, use Gnus native MUA; if it is t, use
-`mail-user-agent'."
+ "Your preferred mail composition package when reading email with message.el.
+Like `mail-user-agent' (which see), this specifies the mail-sending
+package you prefer.
+The value can be any value accepted by `mail-user-agent', and in
+addition it can be nil or t. If the value is nil, use the Gnus native
+Mail User Agent (MUA); if it is t, use the value of `mail-user-agent'."
:version "22.1"
:type '(radio (const :tag "Gnus native"
:format "%t\n"