Variable: mouse-wheel-flip-direction
mouse-wheel-flip-direction is a customizable variable defined in
mwheel.el.gz.
Value
nil
Documentation
Swap direction of wheel-right and wheel-left.
By default, wheel-right scrolls the text to the right,
and wheel-left scrolls in the other direction.
If this variable is non-nil, it inverts the direction of
horizontal scrolling by tilting the mouse wheel.
Also see mouse-wheel-tilt-scroll.
This variable was added, or its default value changed, in Emacs 26.1.
Probably introduced at or before Emacs version 26.1.
Source Code
;; Defined in /usr/src/emacs/lisp/mwheel.el.gz
(defcustom mouse-wheel-flip-direction nil
"Swap direction of `wheel-right' and `wheel-left'.
By default, `wheel-right' scrolls the text to the right,
and `wheel-left' scrolls in the other direction.
If this variable is non-nil, it inverts the direction of
horizontal scrolling by tilting the mouse wheel.
Also see `mouse-wheel-tilt-scroll'."
:group 'mouse
:type 'boolean
:version "26.1")