;; The car of each element in the message-header alist is a symbol whose
;; print name is the name of the header, in all lower-case. The cdr of an
;; element depends on the operation. After extracting headers from a
-;; messge, it is a string, the value of the header. An extracted set of
+;; message, it is a string, the value of the header. An extracted set of
;; headers may be parsed further, which may turn it into a list, whose car
;; is the original value and whose subsequent elements depend on the
;; header. For formatting, it is evaluated to obtain the strings to be