I love ::class

gistfile1.txt

    'zfc_rbac'        => [
        'identity_provider' => UserService::class
    ],
    'controllers'     => [
        'factories' => [
            LoginController::class  => LoginControllerFactory::class,
            LogoutController::class => LogoutControllerFactory::class,
            DetailController::class => DetailControllerFactory::class
        ]
    ],
    'service_manager' => [
        'factories' => [
            AuthenticationService::class             => AuthenticationServiceFactory::class,
            ModuleOptions::class                     => ModuleOptionsFactory::class,
            UserService::class                       => UserServiceFactory::class,
            CreateNotExistingIdentityListener::class => CreateNotExistingIdentityListenerFactory::class,
            UpdateIdentityMetadataListener::class    => UpdateIdentityMetadataListenerFactory::class,
            MapIdentityToObjectListener::class       => MapIdentityToObjectListenerFactory::class
        ]
    ],
    'form_elements'   => [
        'invokables' => [
            LoginForm::class => LoginForm::class
        ]
    ],