Conditional INSTALLED_APPS entry
Some INSTALLED_APPLICATIONS applications may not be critical for your website to work - for example you may only need them for development - like 'django_extensions' or 'debug_toolbar'. They needn't be installed actually for the site to work. This way you can avoid discussions with other developers if some application should be included, or is it just spam, because if they don't like it, they don't have to install it. On a production server you can leave this not installed, to avoid security concerns like a possibility to IP-spoof and see the debug toolbar.
- configuration
- settings
- conditional
- installed_apps