The get accessor of the ApplicationSettingsBase.Properties property reflects over the metadata of the settings wrapper class, which is derived from System.Configuration.ApplicationSettingsBase, to dynamically determine the set of available application settings properties.

The System.Configuration.ApplicationSettingsBase class natively recognizes certain characteristics of an application setting, such as its name, property type, settings provider, default value, read only status, and a serialization preference. These characteristics are mirrored as properties in the System.Configuration.SettingsProperty class. All other attributes of the settings property are just passed through to its associated settings provider.