What this Wordfence script in HTML output mean?

Hello,

I found out that Wordfence outputs this script in HTML code. It is caused only on home/index page. What does it mean?

<script type="text/javascript">
(function(url){
	if(/(?:Chrome\/26\.0\.1410\.63 Safari\/537\.31|WordfenceTestMonBot)/.test(navigator.userAgent)){ return; }
	var addEvent = function(evt, handler) {
		if (window.addEventListener) {
			document.addEventListener(evt, handler, false);
		} else if (window.attachEvent) {
			document.attachEvent('on' + evt, handler);
		}
	};
	var removeEvent = function(evt, handler) {
		if (window.removeEventListener) {
			document.removeEventListener(evt, handler, false);
		} else if (window.detachEvent) {
			document.detachEvent('on' + evt, handler);
		}
	};
	var evts = 'contextmenu dblclick drag dragend dragenter dragleave dragover dragstart drop keydown keypress keyup mousedown mousemove mouseout mouseover mouseup mousewheel scroll'.split(' ');
	var logHuman = function() {
		var wfscr = document.createElement('script');
		wfscr.type = 'text/javascript';
		wfscr.async = true;
		wfscr.src = url + '&r=' + Math.random();
		(document.getElementsByTagName('head')[0]||document.getElementsByTagName('body')[0]).appendChild(wfscr);
		for (var i = 0; i < evts.length; i++) {
			removeEvent(evts[i], logHuman);
		}
	};
	for (var i = 0; i < evts.length; i++) {
		addEvent(evts[i], logHuman);
	}
})('//www.example.cz/TEMP/cs/?wordfence_lh=1&hid=276039FD0FF4B65C54BA8407BFDCEF80');
</script>

Thanks you