The Features module provides an intelligent bundling method that reviews the current Drupal site's configuration and suggests feature modules that should be created to preserve the configuration. These are provided through package assignment plugins.
These plugins use logic to assign configurations to specific packages:
When you visit the Features UI, it will present you with suggested feature modules to be exported. Expanding the items will list the configuration items that will be bundled. Clicking on the suggested feature's link opens the creation form. Alternatively, the checkbox can be used in conjunction with the Download archive or Write button at the bottom of the form.
The unpackaged section shows a configuration that has not met any of the packaging rules to group the configuration into a specified module. This will need to be manually added to a created feature module.