Why Router does not implement RequestHandlerInterface?

[PhantomArt]

Why Router does not implement Psr\Http\Server\RequestHandlerInterface?

It will look closer to the standards:

$response = $router->handle($request);

[Juhlinus]

The dispatcher implements it.

class Dispatcher extends GroupCountBasedDispatcher implements
    MiddlewareAwareInterface,
    RequestHandlerInterface,
    StrategyAwareInterface