: Files with "MPL" in the name generally signal that the contents are under the Mozilla Public License , which allows you to use the code in larger works (even proprietary ones) as long as you keep the original MPL-covered files open and provide notice of changes. Quick Review: 7-Zip (.7z) Format
If you are looking for a review of the archive format itself: MPL.7z
: The format is open-source and supported by a wide variety of tools, including 7-Zip and libraries like bit7z . : Files with "MPL" in the name generally