Today, Apple is releasing GM seeds for iOS 13.5, iPadOS 13.5, and tvOS 13.4.5, meaning that these builds are likely going to be the same ones that go out to the general public. Also, watchOS 6.2.5 has skipped right over the GM phase and is now available to everyone.
iOS and iPadOS 13.5 were originally called version 13.4.5, just like tvOS (they usually all have the same version number), but then a pandemic happened. Originally, the only new features were going to be the ability to share songs, albums, and playlists from Apple Music to Facebook and Instagram.
One new feature that's been added since is Apple's Exposure Notification API, which is meant for contact tracing of people that have been infected with the COVID-19 coronavirus. You can opt into it, and public health applications can access if you've been in contact with anyone else that's opted in. Google is doing the same thing with Android. This feature required a new SDK, which is why the version number changed.
Another new feature is a key Face ID improvement. No, it still won't work with a mask on. It's just slightly better than it was before. Previously, your iPhone would spend a couple of seconds trying to recognize you before allowing you to enter a PIN. Now, it will go directly to the PIN screen. The other COVID-related feature is that FaceTime will no longer enlarge tiles in group calls when someone is speaking.
These updates should all be out really soon, and if you're an Apple Developer, the bits are available. Public beta testers should get the GM seed soon as well.