What is the Mixed Reality Toolkit for Unreal? | One Dev Question

Summer Wu tells us about the Mixed Reality Toolkit for Unreal (and how it differs from the Unity version). For an introduction to Mixed Reality see: 

https://docs.microsoft.com/learn/modules/introduction-dynamics-365/5-mixed-reality?WT.mc_id=onedevquestion-c9-MR2. 

You can find the MRTK for Unreal project on GitHub at https://msft.it/6019pQlER.