CPython and Tcl/Tk: Support/Python/LICENSE.txt (includes third-party notices).
cryptography, cffi, pycparser and bundled OpenSSL notices: the license files
in Support/Python/site-packages/*dist-info/licenses (also included in this package).
Python source: https://www.python.org/downloads/source/
cryptography source: https://github.com/pyca/cryptography
cffi source: https://github.com/python-cffi/cffi
pycparser source: https://github.com/eliben/pycparser
