Designed for the fourth and fifth-generation Apple TV models, the new tvOS 12.2 developer beta can be downloaded onto the Apple TV via a profile that's installed using Xcode.
tvOS updates have historically been minor in scale, focusing on under-the-hood bug fixes and improvements rather than major outward-facing changes. Apple provides little to no information on what's included in tvOS updates, so we may not discover anything new after installing the new beta.
Though we don't often know what's new in tvOS updates, we let MacRumors readers know when new software is available so developers are able to download it upon release. Today's update could, however, include a major new feature -- Apple's updated TV app that's coming in May.
The updated TV app features a revamped design along with new functionality. A new machine learning-powered recommendation engine will surface TV shows and movies that fit with your interests, while a new Channels feature will let you subscribe to and watch content from sources like HBO, Starz, and Showtime right in the app.
Along with tvOS 12.3, Apple has also released a beta version of Apple TV software 7.3, which is designed for the third-generation Apple TV.
Update: Today's tvOS 12.3 update does indeed include the new Apple TV app. The TV app icon itself has also been updated with a new look to match the redesign.