/usr/lib/x86_64-linux-gnu/libassuan.so is in libassuan-dev 2.1.2-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libassuan.so.0.4.2
/usr/lib/x86_64-linux-gnu/libassuan.so.0.4.2