This article explains what an MPK file is, how to open it, and how to convert it to another file format.
Set up data source and share MPK file in ArcGIS
A file with the MPK file extension is an ArcGIS map package file that contains map data (layouts, embedded features, and more) in a single file that is easily distributed. It also contains a map document (.MXD file).
The MPK file extension is also used for Project64 Memory Pack files used by Nintendo 64 emulators.
Map packages and documents (MPK and MXD files) can be opened with Esri's ArcGIS program (v10 and newer).
