+(defcustom notmuch-indent-messages-width 1
+ "Width of message indentation in threads.
+
+Messages are shown indented according to their depth in a thread.
+This variable determines the width of this indentation measured
+in number of blanks. Defaults to `1', choose `0' to disable
+indentation."
+ :group 'notmuch
+ :type 'integer)
+