/usr/lib/x86_64-linux-gnu/libdb_stl.so is in libdb5.3-stl-dev 5.3.28-11.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libdb_stl-5.3.so
/usr/lib/x86_64-linux-gnu/libdb_stl-5.3.so