http://cre.ations.net/blog/post/iphone-113-firmware-behind-the-scenes-changes
- SpringBoard no longer needs to be modified (via SummerBoard) in order to show extra applications in the /Applications folder.
- All applications now run as the user 'mobile' instead of as root.
- Preferences are now stored in /var/mobile rather than in /var/root.
It also appears that the frameworks have undergone many changes, ostensibly to make it easier for official SDK developers to make programs.
Additionally, the SpringBoard app appears to have widget support - it contains a class called SBWidgetApplication which manages the package location and icon.
I will update this post with more details as I find them, so keep checking back.