iOS 9.3 is coming in the Spring and will introduce Night Shift as well as a number of other new features.
Apple Releases iOS 6 Beta 2 to Developers
Beta 2 has a build number of 10A5338d, up from Beta 1's build number of 10A5316k. Apple also released Xcode 4.5 Developer Preview 2 and Apple TV Software beta 2.
Setting icon gears rotate while downloading.