Dragging files out of web page into your local disk?

I just read this blog post and it stated that:

Google is now working on reversing the process -- allowing us to drag files开发者_开发问答 out of Gmail messages and drop them onto our local folders.onto our local folders.

My question is: how is this possible?

It isn't — in current browsers.

It will require browsers to implement an API to make it possible and for pages to make use of that API. That, presumably, is what Google is working on.

Google has its own browser so it is possible with Google Chrome.