The source code

    /**
     * @ignore
     *  normalize mousewheel in gecko
     * @author yiminghe@gmail.com
     */
    KISSY.add('event/dom/base/mousewheel', function (S, special) {

        var UA = S.UA, MOUSE_WHEEL = UA.gecko ? 'DOMMouseScroll' : 'mousewheel';

        special['mousewheel'] = {
            onFix: MOUSE_WHEEL,
            delegateFix: MOUSE_WHEEL
        };

    }, {
        requires: ['./special']
    });