Earlier quoted context omitted.
Looks like it. If you look a the store.js source code, it links to http://msdn.microsoft.com/en-us/library/ms531424(v=VS.85).as... which appears to be another one of those hidden gems in IE, like the original AJAX implementation, or XDomainRequest.
"Hidden?" Give IE some respect...its rendering may have been crap, but it had plenty of features like this for building robust web applications years before the cool kids realized that might be a good idea.
I was doing web dev for an agency back when IE6 was the coolest browser around, and all around me JavaScript was still very much being used only for menus and rollovers. I guess all these features were basically ahead of their time. I'd love to know what Microsoft used them for, or intended them for. I mean, they've been exercising their vested interest in not pushing rich browser-based apps for years. I know their MSDN site has been very AJAX-y since before it was cool.