Last night, Apple posted the third beta of the Dev CenteriOS 10 beta 3 (read: iOS 10 beta 3 available for developers and testers), tvOS 10 and of watchOS 3 (read: tvOS 10 beta 3 and watchOS 3 beta 3 available for developers). A little later, the apple firm released macOS Sierra beta 3. The latter arrives two weeks after the second pre-release.
As a reminder, macOS Sierra beta 2 has brought only one new feature to the operating system dedicated to Macs, namely the possibility of unlocking an Apple computer with the Apple Watch without having to enter a password. This function called Auto Unlock has been awaited for several months by fans of the brand owning these two devices.
If you want to download the third beta of macOS Sierra and you have installed the previous upgrade, go to the tab Updates from the Mac App Store. For the others, you will have to go to the Dev Center if you have a developer account or from the section dedicated to the Apple test program accessible at this address.