Variable: gnus-use-trees
gnus-use-trees is a customizable variable defined in gnus.el.gz.
Value
nil
Documentation
If non-nil, display a thread tree buffer.
Probably introduced at or before Emacs version 19.32.
Source Code
;; Defined in /usr/src/emacs/lisp/gnus/gnus.el.gz
(defcustom gnus-use-trees nil
"If non-nil, display a thread tree buffer."
:group 'gnus-meta
:type 'boolean)