/usr/lib/x86_64-linux-gnu/libmdb.so is in mdbtools-dev 0.7.1-6.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libmdb.so.2.0.1
/usr/lib/x86_64-linux-gnu/libmdb.so.2.0.1