A good practice in applications design is making use of componentization and loose coupling. Ideally, components should have no knowledge of other components except for their interface or events. This allows reusing components over different applications or swapping out components with other implementations.
Symfony provides the EventDispatcher component that lets your application components communicate with each other by dispatching events and listening to them.
Code completion in events
Provide events' names to the relevant functions when dispatching or subscribing to events.
Provide events' names within an array of all events you're subscribing to, which is required for implementing
Code navigation in events
If several declarations are located, choose a specific one to navigate to from the popup menu.