What is ADFU?
 

I came across the term "ADFU device" for the first time just a few minutes ago. Searching with google hasn't helped me figure out what it is, although I now know that there is something called "ADFU mode" as well, and that an ADFU device may just be a media player or other USB device in ADFU mode.

But what is it? Anything to do with MSC/UMS and MTP modes?

BTW, I'm a Mac and UNIX user, and most of the references I've seen for ADFU seem to be related to MS Windows, and particularly to drivers for same.