The biggest announcement from WWDC so far (In my opinion) and can't find any discussion of it here:
http://arstechnica.com/apple/2015/0...ajor-boon-for-8gb-and-16gb-iphones-and-ipads/
iOS 9 App Thinning/Slicing and Unity?
http://arstechnica.com/apple/2015/0...ajor-boon-for-8gb-and-16gb-iphones-and-ipads/