On 28 Feb 2018 8:29 a.m., "Tak Kunihiro" <tkk@misasa.okayama-u.ac.jp> wrote:

I’m sending a patch to change names
from mwheel-tilt-scroll-p and mwheel-flip-direction
to   mwheel-wheel-tilt-scroll and mwheel-wheel-flip-direction.

* Commit log

    Change name of variables to be consistent

    Variables mwheel-tilt-scroll-p and mwheel-flip-direction were
    renamed to mwheel-wheel-tilt-scroll and
    mwheel-wheel-flip-direction.  Suggested by Glenn Morris
    <rgm@gnu.org> in emacs-devel@gnu.org.

    * lisp/mwheel.el (mwheel-wheel-tilt-scroll):
    (mwheel-wheel-flip-direction):
    * etc/NEWS:
    * doc/emacs/frames.texi (Mouse Commands): Variables are renamed.