KMZ is a file extension for a placemark file used by Google Earth. A tool that views the KML, KMZ (Zipped KML format) file on a map. A KMZ file consists of a main KML file and zero or more supporting files that are packaged using a Zip utility into one unit, called an archive. KMZ is a file extension for a placemark file used by Google Earth. If you have a KML or KMZ file from an older version of Google Earth, you can open it in Google Earth for Android. What Is a KMZ File? KMZ files are very similar to ZIP files.