I was curious about the pypm binary package format. They are in the .tar.gz format (but with .pypm extension). They contain two files: info.json: {u'author': u'Zope Foundation and Contributors', u'author_email': u'zope-dev@zope.org', u'description': '...', u'home_page': u'http://pypi.python.org/pypi/zope.interface', u'install_requires': {u'': [u'distribute'], u'docs': [u'z3c.recipe.sphinxdoc'], u'test': [u'zope.event']}, u'keywords': None, u'license': u'ZPL 2.1', u'maintainer': None, u'maintainer_email': None, u'name': u'zope.interface', u'osarch': u'win32-x86', u'pkg_version': 1, u'pyver': u'2.7', u'summary': u'Interfaces for Python', u'version': u'3.8.0'} data.tar.gz: Lib/site-packages/zope.interface/... (including .pyd or .so) Lib/site-packages/zope.interface-3.8.0-py27.egg-info/(normal egg-info stuff) When installed, Lib/ is unpacked into %APPDATA%\Python\Python27\site-packages\