Apple today seeded Developer Beta 3 of iOS 10.1, tvOS 10.0.1, and Xcode 8.1. Today's new builds come just six days after their predecessors, which were accompanied by a watchOS 3.1 beta. Like watchOS, there's no new macOS 10.12.1 Sierra build today, for which the third beta was released seven days ago.
iOS 10.1 doesn't include any major new features, unless you have an iPhone 7 Plus, in which case the camera now offers Portrait Mode, which will give a photo a blurred background. As you can see from our review of the device, the feature doesn't work very well right now; however, it's still in beta and should get better with time.
tvOS 10.0.1, on the other hand, provides nothing of note. In fact, Apple's release notes say that it includes "bug fixes and improvements in the OS". Xcode updates tend to come alongside OS updates, and they generally include support for updated SDKs.
Today's builds are only for developers, so if you're on the Public Beta program, you'll likely have to wait until tomorrow to grab iOS 10.1 beta 3. As usual, there is no Public Beta for tvOS.