in assets/js/slick.js [2419:2461]
    Slick.prototype.setupInfinite = function() {
        var _ = this,
            i, slideIndex, infiniteCount;
        if (_.options.fade === true) {
            _.options.centerMode = false;
        }
        if (_.options.infinite === true && _.options.fade === false) {
            slideIndex = null;
            if (_.slideCount > _.options.slidesToShow) {
                if (_.options.centerMode === true) {
                    infiniteCount = _.options.slidesToShow + 1;
                } else {
                    infiniteCount = _.options.slidesToShow;
                }
                for (i = _.slideCount; i > (_.slideCount -
                        infiniteCount); i -= 1) {
                    slideIndex = i - 1;
                    $(_.$slides[slideIndex]).clone(true).attr('id', '')
                        .attr('data-slick-index', slideIndex - _.slideCount)
                        .prependTo(_.$slideTrack).addClass('slick-cloned');
                }
                for (i = 0; i < infiniteCount  + _.slideCount; i += 1) {
                    slideIndex = i;
                    $(_.$slides[slideIndex]).clone(true).attr('id', '')
                        .attr('data-slick-index', slideIndex + _.slideCount)
                        .appendTo(_.$slideTrack).addClass('slick-cloned');
                }
                _.$slideTrack.find('.slick-cloned').find('[id]').each(function() {
                    $(this).attr('id', '');
                });
            }
        }
    };