In an interview with Daily Star Online, creative director Ralph Fulton confirmed that Xbox One X will be the "lead platform" for Playground's next project, which is heavily rumored to be a new game in the Fable series.
Reflecting on the studio's currently undisclosed project, Fulton said, "Ease of development in the Xbox One X's make up provides a really great development platform," Fulton said, "not just for that console but also the whole family of devices and even PC." He also asserted that focusing on the X as a development platform means all Xbox One family versions will see improvement.
"[Xbox consoles] have always been good consoles to work on" Fulton said, "but in terms of the power the Xbox One X has on your desk, it's a fantastic bit of kit for developers."
I also found this quote in the Digital Foundry interview with PlayGround Games:
We are obviously beginning development on a new unannounced title right now. And the development platform for that game is Xbox One X, which is great for us, and ultimately for the players in a number of ways. First of all, it's great to develop for, it's incredibly powerful, it has more memory than we've ever had. So it's a great piece of kit to be developing your game on. And the easier and faster you can develop, the more things you can get done.
They also say that this will help them with developing for Xbox One S;
I definitely think that during development, we see trickle down benefits to other platforms we develop for, such as the Xbox One, or even PC. And I think that comes from the standardized unified test tools we are working on."
I feel like this is significant for a number of reasons: the most important is that it seems like Playgrounds' game will be coming to Xbox One. I know many speculated that it may be an Xbox Two game or whatever, but it is now clear it is being made for the Xbox One spec. The other important takeaway here is that Microsoft's internal games are apparently now being made for the Xbox One X spec, and downported from there to the Xbox One S. I don't know what this means in the long run, but it is interesting to consider nonetheless.