Apple has released the sixth beta of tvOS 13 to the developers

Overview
The tvOS 13 SDK provides support for developing tvOS apps for Apple TV devices running tvOS 13. The SDK comes bundled with Xcode 11 beta available from Beta Software Downloads. For information on the compatibility requirements for Xcode 11, see Xcode 11 Beta 5 Release Notes.

AuthenticationServices
Known Issues
Passing both ASAuthorizationAppleIDProvider and ASAuthorizationPasswordProvider to ASAuthorizationController is not currently supported on tvOS. (50897359)

AVFoundation
New Features
AVFoundation now supports encoding video with alpha channels using HEVC. Videos encoded in this manner are broadly supported in AVFoundation APIs, and by Safari within web pages. Technical details of the format can be found in the Interoperability Profile specification. (8045917)

  tvOS 13 Beta 6 released