Back in January 2015, when Microsoft first announced Windows 10 at its "Windows 10: The Next Chapter" event, the company also revealed its Microsoft HoloLens augmented reality (AR)/mixed reality (MR) headset. Microsoft has big ambitions for MR, in a way that's a bit similar to what the company is now looking forward to with Copilot on the next generation of Windows, so much so that Microsoft CEO Satya Nadella feels it's as big and important as the Start button itself.
At that time, HoloLens and its supporting platform framework were called "Windows Holographic", but in 2017, it was renamed "Windows Mixed Reality".
While it may be a little hard to fathom now, Microsoft's outlook wasn't wrong, as at the time, VR and AR seemed to be the next big thing. The tech giant naturally jumped on this train because it didn't want to be left behind, as almost everyone else was doing. However, it can be said that the entire industry, including Microsoft, may have overestimated the potential of MR, so the company has no other business except developing business in some niche markets.
Perhaps this is why Microsoft has now announced that it is abandoning the Windows Mixed Reality platform. On a webpage outlining the deprecated Windows client features, Microsoft added a section for Windows Mixed Reality, where it noted that Windows Mixed Reality will be deprecated along with the Mixed Reality Portal app and Windows MR for SteamVR and SteamVR beta:
https://learn.microsoft.com/en-us/windows/whats-new/deprecated-features#deprecated-features
Windows Mixed Reality has been deprecated and will be removed in a future version of Windows. This deprecation includes the Mixed Reality Portal application, Windows Mixed Reality for SteamVR and SteamVR beta.