FastStart-enabled games prioritize the most important parts of the game first, saving the rest of the data to download in the background while you're playing the first few minutes of the game. Either way, this has made for a hilarious mistake to point out, especially since it's an Xbox-centric app with rewards localized to Microsoft customers. The survival-centric multiplayer game has gone free-to-play on Xbox One, much like the current Steam Early Access version.
The two big caveats here, though, are that games need to be FastStart-enabled by Microsoft and you'll need a download speed of around 20Mbps. Your groups will appear under My Games and Apps, in Home, and in the Guide.
According to Microsoft, games that utilize the feature will half the amount of time it takes from when a download begins to the moment you're actually able to play it. There's also a mechanic that allows you to track other players in order to hunt them down and take them out.
As an added bonus, Groups will be tied to your Xbox Live account and will automatically sync across multiple Xbox One consoles. This process is found in many apps, but now you can do it anywhere within the dashboard. Mixer's also been given some attention, with full mouse and keyboard support for PC users and Share Controller key bindings now at your disposal. Hit enter or click the "more results" button to view a full page for your search results. Hyrb said this feature is "perfect for talking to your audience while switching from game to game or setting up before you start playing". You can switch to full screen webcam broadcasting at any time you want. You can even do all IRL broadcasts!
The July Xbox update launches later today.
The update is mostly concerned with making it easier for users to find content, as well as improving Mixer.