/usr/lib/python3/ is in software-properties-gtk 0.96.20.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/python3/dist-packages/
/usr/lib/python3/dist-packages/softwareproperties/
/usr/lib/python3/dist-packages/softwareproperties/gtk/
/usr/lib/python3/dist-packages/softwareproperties/gtk/DialogAddSourcesList.py
/usr/lib/python3/dist-packages/softwareproperties/gtk/DialogCacheOutdated.py
/usr/lib/python3/dist-packages/softwareproperties/gtk/DialogAdd.py
/usr/lib/python3/dist-packages/softwareproperties/gtk/__init__.py
/usr/lib/python3/dist-packages/softwareproperties/gtk/SimpleGtkbuilderApp.py
/usr/lib/python3/dist-packages/softwareproperties/gtk/SoftwarePropertiesGtk.py
/usr/lib/python3/dist-packages/softwareproperties/gtk/DialogMirror.py
/usr/lib/python3/dist-packages/softwareproperties/gtk/CdromProgress.py
/usr/lib/python3/dist-packages/softwareproperties/gtk/dialogs.py
/usr/lib/python3/dist-packages/softwareproperties/gtk/utils.py
/usr/lib/python3/dist-packages/softwareproperties/gtk/DialogEdit.py