The MSIX Packaging SDK project is an effort to enable developers on a variety of platforms to pack and unpack packages for the purposes of distribution from either the Microsoft Store, or their own content distribution networks. The MSIX Packaging APIs that a client app would use to interact with .msix/.appx packages are a subset of those documented at https://msdn.microsoft.com/en-us/library/windows/desktop/hh446766.aspx . See https://github.com/Microsoft/msix-packaging/blob/master/sample/ExtractContentsSample/ExtractContentsSample.cpp for additional details. The MSIX Packaging SDK project includes cross platform API support for unpacking of .msix/.appx packages

msix: A shared library (DLL on Win32, dylib on MacOs, SO on Linux and Android) that exports a subset of the functionality contained within appxpackaging.dll on Windows. See here for additional details. On all platforms instead of CoCreating IAppxFactory, a c-style export: CoCreateAppxFactory is provided. See sample folder at root of package for cross platform consumption examples. Finally, there is one export 'Unpack' that provides an simplified unpackage implementation. makemsix: A command line wrapper over the Unpack implementation. This tool exists primarily as a means of validating the implementation of the MSIX Packaging SDK internal routines and is compiled for Win32, MacOS, and Linux platforms.