/usr/lib/x86_64-linux-gnu/libdb.a is in libdb5.3-dev 5.3.28-13.1ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libdb-5.3.a
/usr/lib/x86_64-linux-gnu/libdb-5.3.a