Upon running WACK, you're presented with four options:
Validate Windows Store App
Validate Windows Phone App
Validate Desktop App
Validate Desktop Device App
All of them seem pretty self-explanatory, except for the last one, "Validate Desktop Device App". It's described as "Test a desktop device app for compliance with value-added software requirements". Huh?
Searching Microsoft and MSDN for the phrase "value-added software requirements" turns up zero results. Searching for just "value-added software" (isn't all software value-added?) led me to this post on Raymond Chen's The Old New Thing blog which indicates that "value-added software" is the crapware/shovelware that's pre-installed on computers bought at, say, Best Buy.
I really wish Microsoft would focus less on consistent branding and more on actually explaining things. Incidentally, I gagged a little bit when I read the phrase "Validate Desktop App".