You can add "?debug=true" to the URL to reveal all the available JavaScript sources, as described in the "Test It" section of the below article.
https://jazz.net/library/article/1360
No dojox.data.XmlStore.js can be seen unfortunately. The closer ones are dojox.data.dom.js and dojox.xml.DomParser.js.

Hy Robert,

First, I think you might have a typo-error...
It's called "dojox" and not "doDjox" --> There's a d too much.

But in future I'll show you a little trick to check if something is loaded or not.

1: Require how you want it.
dojo.require("dojox.data.XmlStore");

2: Make a variable out of it. (Between, "(function(){"  and "dojo.declare()")
var XmlStore = dojox.data.XmlStore;

3: Now you just can "console.log()" it.
console.log(XmlStore);

4: If there are shown some functions (or just one). It was probably loaded.

----And Donald told it right----
For more information, you can use "?debug=true" in your URL to get more adequate informations.

P.S.
To prevent more questions. Watch this link. There's a list of useful links to watch about Dojo.

https://jazz.net/forum/questions/157077/does-someone-has-usefull-links-for-dojojs#160529