15 files declare their use of GroupTypeInterface in Group 8

GroupContentEnablerManager.php in src/Plugin/GroupContentEnablerManager.php

GroupContentEnablerManagerInterface.php in src/Plugin/GroupContentEnablerManagerInterface.php

GroupContentTypeStorage.php in src/Entity/Storage/GroupContentTypeStorage.php

GroupContentTypeStorageInterface.php in src/Entity/Storage/GroupContentTypeStorageInterface.php

GroupController.php in src/Entity/Controller/GroupController.php

GroupPermissionHandler.php in src/Access/GroupPermissionHandler.php

GroupPermissionHandlerInterface.php in src/Access/GroupPermissionHandlerInterface.php

GroupPermissionsTypeSpecificForm.php in src/Form/GroupPermissionsTypeSpecificForm.php

GroupRoleListBuilder.php in src/Entity/Controller/GroupRoleListBuilder.php

GroupRoleSynchronizer.php in src/GroupRoleSynchronizer.php

GroupTypeController.php in src/Entity/Controller/GroupTypeController.php

GroupTypeCreateTest.php in tests/src/Kernel/GroupTypeCreateTest.php

GroupTypeForm.php in src/Entity/Form/GroupTypeForm.php

GroupTypeTest.php in tests/src/Kernel/GroupTypeTest.php

RouteGroupCacheContextTest.php in tests/src/Unit/RouteGroupCacheContextTest.php