/usr/lib/x86_64-linux-gnu/libopenblas.a is in libopenblas-dev 0.2.20+ds-4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libopenblasp-r0.2.20.a
/usr/lib/x86_64-linux-gnu/libopenblasp-r0.2.20.a