+(defcustom nnmail-cache-ignore-groups nil
+ "Regexp that matches group names to be ignored when inserting message
+ids into the cache (`nnmail-cache-insert'). This can also be a list
+of regexps."
+ :group 'nnmail-split
+ :type '(choice (const :tag "none" nil)
+ (regexp :value ".*")
+ (repeat :value (".*") regexp)))
+