You can define which feature types are available within a domain, i.e. which feature types will be available for creating new features within a domain. Setting the availability of feature types on a domain will not influence visibility or existence of already existing features in that domain.

For a feature type to be available in a specific domain it must be available on all domains in the specific domains path, or the other way round if a feature type is marked to be not available in one domain it will not be available in that domain and all of its subordinate domains.

By default i.e. when a domain is created, all feature types are available.