Xbox has passed at least three prior Xbox Developer Kits through the National Radio Research Agency. This included the Xbox One X and Xbox Series X|S. You can independently verify this by checking ...

There are reports of a new Xbox development kit being certified ... the impression that Sony is working on a beast of a console, one that will outstrip the base PS5's graphical capabilities ...

It was suggested to be $499 though, which is around £50 cheaper than the current Xbox Series X model. The other possibility is that the dev kit is for an actual next gen Xbox, with some rumours ...