As well as the new updates for iOS and macOS, Apple also released some updates for the Apple Watch in the form of watchOS 6.2.6 and the Apple TV in the form of tvOS 13.4.6.
The new tvOS 13.4.6 and watchOS 6.2.6 do not appear to come with any major new features, the do comes with some security fixes.
Apple’s recent release od iOS 13.5.1 was designed to fix a security vulnerability in Apple’s mobile OS that allowed for the Unc0ver jailbreak to work. This has now been patched in the latest iOS update.
The new tvOS and watchOS software updates probably fix the same security issue, although Apple has not specified exactly what has changed in these software updates.
Source Apple