On , I learnt ...

Django settings prefixed with an underscore are private

As in: you can’t access them from outside the settings module.

If you have:

_FOO = 1

in your settings module, then this test:

from django.conf import settings

def test_private_settings_are_inaccessible():
    assert settings._FOO == 1

will fail with error:

AttributeError: 'Settings' object has no attribute '_FOO'