/usr/lib/x86_64-linux-gnu/libpython3.5dm.so.1 is in libpython3.5-dbg 3.5.1-10.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libpython3.5dm.so.1.0
/usr/lib/x86_64-linux-gnu/libpython3.5dm.so.1.0