Back in April, the Xbox Insider Hub showed up in the Windows Store on PCs. At the time, you could download the app, but it would only display a "coming soon" message when it was opened. Today though, the app is finally available for PCs running the Anniversary Update (build 14393) or higher.
Unfortunately, there's still no Windows 10 Mobile support, and there's no evidence that it's coming at all. Users that have 32-bit PCs will also be left out on this one, as while the app will still be searchable in the Store, it will display a message that says "See Available on for devices this product works on. It won't run on this one."
Since Xbox Insider Hub is a UWP app, it functions in the same way that it does on an Xbox One. It's a bit bare for the time being, not offering any new Quests. You'll likely find one Survey that asks about your experience with the app on your PC, and you might find a Quick poll and the opportunity to Rate content.
If you want to install the Xbox Insider Hub on your PC, you can find it in the Windows Store here.