initialPage property of the sap.m.App in the HelloWorld Tutorial

Hello,

This question might sound very basic for many however as a starter I would like to clear this doubt.

var App = new sap.m.App("first", {initialPage:"firstpage"};

In the above code I was trying to locate the property (initialPage) of the API App in the "UI Development toolkit for HTML5 - Demo Kit" API Reference section. But I couldn't find it. I can see some properties as shown below but not initialPage Property. Could someone help on how to find the properties of an API?

Regards

Sha