rmail-speedbar-buttons
rmail-speedbar-buttons is a compiled Lisp function in `rmail.el
'.
(rmail-speedbar-buttons BUFFER)
Create buttons for BUFFER containing rmail messages.
Click on the address under Reply to: to reply to this person.
Under Folders: Click a name to read it, or on the <M> to move the
current message into that RMAIL folder.