How is jQuery able to normalize currentTarget for IE?

Question

In an event handler in a standard compliant browser, this and e.currentTarget (where e is the parameter of the handler) refer to the element to which the handler is attached, which by the way isn't necessarily the same as e.target.

Problem is, there is no e.currentTarget in old versions of Internet Explorer.

In old IE, this in an event handler is simply the global object and e is undefined and window.event.srcELement is just equivalent to e.target and not to e.currentTarget.

Question is, what kind of magic is jQuery pulling off to make e.currentTarget work even in IE?