Mixed Reality Toolkit
Mixed Reality Toolkit (MRTK) is an open-source software development kit (SDK) developed by Microsoft in 2016 for the development of mixed reality (MR) and augmented reality (AR) software applications. It consists of a collection of components and features designed to enhance the mixed reality user and developer experiences. The toolkit was originally developed by Microsoft for the release of the HoloLens 1 augmented reality headset, although it supports a variety of platforms. History

Initial release 

Known as the "HoloToolkit" (HTK) prior to its initial public release, the software development kit was created to aid in the development of the new Microsoft HoloLens augmented reality device. Mixed Reality Toolkit was released to the public as an open-source SDK in December 2017, one year after the release of Microsoft's HoloLens. The software has had multiple successful generations, including MRTK, MRTK2, and the soon-to-be-released MRTK3. Layoffs 
On January 18, 2023, Microsoft announced that it would be laying off approximately 10,000 employees. Days later, these layoffs were found to include the entire team behind the development of MRTK, along with significant portions of the HoloLens hardware team. Currently, the future of MRTK is uncertain, although it is expected that the extended reality (XR) community will continue to maintain the software due to it being released as open-source under the MIT License. Supported platforms 
Mixed Reality Toolkit is considered to be a platform-agnostic tool as it features a wide variety of supported platforms. This high level of compatibility allows developers to quickly and easily build mixed reality applications tailored to the specific platform they are working on. The following is a list of supported platforms:

Components and features 
Mixed Reality Toolkit is equipped with a range of components and features that allow developers to create immersive mixed reality applications. These provide developers with a broad range of tools and technologies, including low-level APIs and high-level development frameworks. These components and features are designed to be used in combination with additional software libraries to create engaging and interactive mixed reality experiences. MRTK contains UX building block components, which include buttons, object manipulators, system keyboards, object collections, and more. These tools are provided to developers with the intention of simplifying the development process and encouraging innovation in mixed reality. See also 
 Microsoft HoloLens
 HoloLens 2
 Windows Mixed Reality
 OpenXR
 Augmented reality
 Mixed reality

References

External links 
 MRTK2-Unity Developer Dokumentation - MRTK 2 (Microsoft Learn)
 

2017 software
Augmented reality
Mixed reality
Microsoft free software
Software using the MIT license