TYPO3 Core

The newly introduced Backend Routing is updated so that Routes
must define not just the controller but also the action which should
be called. It is now also possible to use a Closure / callable directly
to be called as a Route.

The RequestHandler now creates the Response object, which is handed to the Dispatcher and to the respective action. This way
each action can already use the existing Response object.

The Dispatcher resolves the action and hands over the request and
response action.

All existing Routes have been adapted to use controller and actions.

The fixed ControllerInterface is not needed anymore (but still in use for eIDs currently).

A similar approach will follow for Backend AJAX Requests.