Variable: mwheel-scroll-up-function
mwheel-scroll-up-function is a variable defined in mwheel.el.gz.
Value
scroll-up
Documentation
Function that does the job of scrolling upward.
Source Code
;; Defined in /usr/src/emacs/lisp/mwheel.el.gz
(defvar mwheel-scroll-up-function 'scroll-up
"Function that does the job of scrolling upward.")