pip's User-Agent field looks like this:
pip/9.0.1 {"cpu":"i686","distro":{"id":"jessie","libc":{"lib":"glibc","version":"2.19"},"name":"Debian GNU/Linux","version":"8"},"implementation":{"name":"CPython","version":"3.4.2"},"installer":{"name":"pip","version":"9.0.1"},"openssl_version":"OpenSSL 1.0.1t 3 May 2016","python":"3.4.2","system":{"name":"Linux","release":"3.16.0-4-686-pae"}}
That's a lot of information about my system.
PyPI has no business knowing my OpenSSL version, my libc version, or my kernel version.
Please trim this down.