* nnmail.el (nnmail-extra-headers): Clarify slightly (bug#9302).

diff --git a/lisp/nnmail.el b/lisp/nnmail.el
index 8906a03..dc2080d 100644 (file)
--- a/lisp/nnmail.el
+++ b/lisp/nnmail.el
@@ -554,7 +554,9 @@ parameter.  It should return nil, `warn' or `delete'."
                 (const delete)))
 
 (defcustom nnmail-extra-headers '(To Newsgroups)
-  "*Extra headers to parse."
+  "Extra headers to parse.
+In addition to the standard headers, these extra headers will be
+included in NOV headers (and the like) when backends parse headers."
   :version "21.1"
   :group 'nnmail
   :type '(repeat symbol))