The wpcrm_system_default_user_roles filter defines the user roles that could potentially be used to access WP-CRM System data.
The filter is passed an array of user roles:
$roles = array( 'subscriber', 'contributor', 'author', 'editor', 'administrator' );
For each user role that is returned, the function will check to see if users in that role should be able to edit WP-CRM System data. If they can it will add the necessary capabilities for the user's role. If they cannot edit WP-CRM System data, it will remove those capabilities.