Do we have any documentation for "anonymous services"? i googled some terms about this feature but not getting results on the official page. Some improvements would be nice here. :)

related: Haehnchen/idea-php-symfony2-plugin#595

The XML format supports anonymous services. An anonymous service is a service that does not need a name and is defined directly in its use context. It can be very convenient when you need a service that won't be used outside of another one scope:
http://fabien.potencier.org/symfony-service-container-using-xml-or-yaml-to-describe-services.html