/usr/share/man/man1/python3.5dm.1.gz is in python3.5-dbg 3.5.3-1+deb9u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/man/man1/python3.5.1.gz
/usr/share/man/man1/python3.5.1.gz