/usr/lib/atlas-base/libcblas.so.3 is in libatlas3-base 3.10.3-1+b1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/atlas-base/libcblas.so.3.0
/usr/lib/atlas-base/libcblas.so.3.0