This also marks the first public beta for iPadOS, Apple's newly forked tablet interface. On top of features borrowed from iOS, you'll see an information-packed home screen, desktop-grade web browsing, the ability to run multiple instances of the same app, support for external storage and other more PC-like overhauls.

For macOS Catalina, meanwhile, it's mostly about the apps. There are now separate Music, Podcasts and TV apps, not to mention voice control over the operating system and the option of using an iPad as a secondary display. Some developer-oriented features, like Project Catalyst, won't really be useful in the public beta -- those will have to wait until apps built around the iOS-to-Mac technology are available.