MIT OS license.
If you’d like to add drag and drop to your application, there’s an open source framework for that. Not only will it work within your own application, but it will also work between DragKit enabled applications.
It was developed for iOSDevCamp 2010 and won the award for best open source project. Created by Zac White with help from Barry Burton and Andy Mai.
Check out the branches that have been made at the github destination.