Project Keystone is Microsoft's Affordable Xbox Cloud Gaming Streaming Stick - IGN
Microsoft has confirmed that it is working on an affordable streaming device capable of streaming Xbox games through the cloud. Windows Central reports that it received confirmation from Microsoft that its streaming dongle - codenamed 'Project Keystone' - is meant to be an easy and affordable option for people that want to play and access games on Xbox Cloud Gaming.
https://www.ign.com/articles/xbox-cloud-gaming-streaming-device-project-keystone

Microsoft confirms work on "Keystone" Xbox game streaming dongle
Microsoft's long-in-the-works xCloud streaming device is going through some changes, as reported by Windows Central . The company first announced the dedicated streaming dongle in June 2021, but in a statement given to Windows Central, the company said it has pivoted from the "current iteration" of the device, which it says is codenamed Keystone.
https://www.theverge.com/2022/5/26/23143181/microsoft-keystone-xbox-xcloud-game-streaming-dongle-codename

Seonglae Cho