If you've opted into the Skip Ahead subset of the Preview Alpha ring on your Xbox One console, today is a big day, as you'll be receiving the first 19H2 build, which will be version 1910. While Microsoft's Brad Rossetti announced the build on Twitter, there aren't any release notes.
It's likely that there won't be any new features yet. Remember, the Xbox Insider Program works differently than the Windows Insider Program, because the Xbox One family of gaming consoles is updated more frequently than twice per year. Yes, there are the two major updates that align with Windows 10, but there are also minor feature updates between those.
It's reasonable to assume that - just as was the case with 19H1/1904 - the features that show up in the minor feature updates over the next few months will be the same that show up in 19H2.
Today's new build is also different from the Windows Insider Program as the Skip Ahead ring on Windows is getting builds from the 20H1 development branch, which won't be finalized until the first half of next year. 19H2 will be exclusive to the Fast ring on Windows 10, and it won't show up until Windows 10 version 1903 ships.
As is the case on Windows though, enrollment in Skip Ahead on Xbox is limited. If you haven't already signed up, you're probably out of luck.