Why did Django 1.9 replace tuples () with lists [] in settings and URLs?

I am bit curious to know why Django 1.9 replaced tuples () with lists [] in settings, URLs and other configuration files

I just upgraded to Django 1.9 and noticed these changes. What is the logic behind them?

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles'
    ]

AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]


STATICFILES_DIRS = [
    os.path.join(BASE_DIR, 'static'),
]

urls.py

urlpatterns = [
    url(r'^', admin.site.urls),
]

Is anything different because of these changes?