Project Mu is mostly about getting the messy parts of the UEFI ecosystem sorted out: Instead of hoping that IBVs ("Independent BIOS Vendors") clean up their act (because, to be frank, they don't), they get ready-to-use components that Microsoft is using itself on the Surface products and provide a certain baseline standard (security, UX, ...).
The difficult part about firmware in general (hardware initialization) is still under lock and wrap though: you'll have to get it from the silicon vendors and link it with the open EDK2/Tianocore (which is the UEFI base) and Mu (which is a toolset to extend that base) components to a full firmware image. In particular, those components aren't distributed as part of EDK2 or Mu.
The difficult part about firmware in general (hardware initialization) is still under lock and wrap though: you'll have to get it from the silicon vendors and link it with the open EDK2/Tianocore (which is the UEFI base) and Mu (which is a toolset to extend that base) components to a full firmware image. In particular, those components aren't distributed as part of EDK2 or Mu.