This is a pre-release version of iOS 9.2 for iPhone, iPad, and iPod touch. Devices updated to iOS 9.2 can not be restored to earlier versions of iOS.
Previously builds of iOS 9.2 beta have brought support for AT&T NumberSync and an improved View Controller for Safari. We'll let you know if there is anything new in the third beta.
Developers can download the beta from the link below...