built-package format for Python (wheel wheel)

 A wheel is a ZIP-format archive with a specially formatted filename and the
 `.whl` extension. It is designed to contain all the files for a PEP 376
 compatible install in a way that is very close to the on-disk format.
 .
 This is the support package for the PEP 427 wheel version of the package,
 required for using wheel inside a virtual environment.