/usr/lib/python3.7/tkinter/tix.py is in python3-tk 3.6.5-3.
This file is owned by root:root, with mode 0o644.
It is a symlink to /usr/lib/python3.7/tkinter/./usr/lib/python3.6/tkinter/tix.py
/usr/lib/python3.7/tkinter/./usr/lib/python3.6/tkinter/tix.py