How to download new Xbox Insider Hub

Maybe it is a little bit confusing to find it. New UI is in the development and you can contribute to this. Join an insider program, or just download an insider hub on your Xbox and report this through your insider hub. It will be immediately noticed.

How to provide feedback as an Xbox Insider: https://support.xbox.com/en-US/xbox-one/console/xbox-insider-hub-report-a-problem

You don't have to be part of the Insider program, just download the Insider Hub app to provide your feedback.

I have noticed that on mine also. It must be a new build in Xbox update. I will report this through an insider hub as I am an Xbox insider. You can do the same. Download an insider hub on your xbox and report this. It will be noticed immediately.

just download The Insider Hub app, on your xbox, and you should be able to pick up new features before they are released

I assume a public operating system build - how would i know?

If you have owned the console since new and never enrolled in the Xbox Insider preview (downloaded the Xbox Insider Hub and joined) then you will be on a public build. If it is a pre owned console, then download the Insider Hub app from the Xbox store and
open it. On the left hand side of the landing screen you will see settings, open that and go to manage devices. It will show there if it is enrolled and you can remove it if it is. They do recommend not using an extension (though most I would suspect, here
in the UK do)