| Attribute |
| Debug |
| DependencyInjection |
| EventDispatcherInterface | The EventDispatcherInterface is the central point of Symfony's event listener system. |
| EventSubscriberInterface | An EventSubscriber knows itself what events it is interested in. |
| EventDispatcher | The EventDispatcherInterface is the central point of Symfony's event listener system. |
| GenericEvent | Event encapsulation class. |
| ImmutableEventDispatcher | A read-only proxy for an event dispatcher. |
| LegacyEventDispatcherProxy | A helper class to provide BC/FC with the legacy signature of EventDispatcherInterface::dispatch(). |