/usr/lib/x86_64-linux-gnu/libpython2.7.a is in libpython2.7-dev 2.7.9-2+deb8u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/../python2.7/config-x86_64-linux-gnu/libpython2.7.a