It's well-known by now that Apple's public software betas usually arrive one day after the beta releases for developers, and the fifth developer betas released yesterday for iOS 13, iPadOS 13, and tvOS 13 are no exception. Today, the equivalent public betas have been released, including the same changes as the builds released yesterday.
As reported by 9to5Mac, these updates include the ability to set the icon density in the home screen on iPadOS 13, choosing between 4x5 grid or a 6x5 grid of apps, and some other changes, including new wallpapers and a redesigned share sheet. The tvOS 13 beta doesn't seem to have any noteworthy additions.
The fifth developer beta for watchOS 6 was also released today since it was seemingly forgotten yesterday when all the other ones were released. It doesn't seem to include any big changes and should mostly focus on fixing any issues that were present in previous beta releases.
These updates will be generally available in the fall, likely around the same time as the new iPhone models are released, which usually happens in September.