ESRI Map Package
Specific software is required to open an ESRI Map Package. For more information on the creation and use of Map Packages, please see Esri.com ArcGIS Desktop is required to open Map Packages
ESRI Map package file format. The map package file format allows the creator to save a map, data and style properties in one complete file. this means the whole map can be provided to anther ESRI ArcGIS user.