https://wccftech.com/apple-releases-beta-1-of-tvos-12-4-macos-10-14-6-watchos-5-3-to-developers/

Today, Apple has seen fit to release the first beta of watchOS 5.3, tvOS 12.4 and macOS 10.14.6 to developers. The new beta versions arrive just a few days after the company seeded macOS 10.14.5, tvOS 12.3 and watchOS 5.2 to the general public. Let’s dive in to see some more details on the new beta build of the aforementioned updates and how you can install them.

Starting off with macOS 10.14.6 beta 1, registered developers can download the latest build through the Software Update mechanism in System Preferences. However, be sure to note that a proper configuration profile is installed through the Developer Center.