How it works...

Installation profiles work by including additional modules that are part of the contributed project realm or custom modules. The profile will then define them as dependencies to be installed with Drupal. When you select an installation profile, you are instructing Drupal to install a set of modules on installation.

Demo Framework declares itself as an exclusive installation profile. Distributions that declare this are automatically selected and assumed to be the default installation option. The exclusive flag was added with Drupal 7.22 to improve the experience of using a Drupal distribution (http://drupal.org/node/1961012).