core-bundle/src/DependencyInjection/Compiler/RegisterFragmentsPass.php
protected function getControllerName(Reference $reference, array $attributes): string
    {
        $controller = (string) $reference;

        // Support a specific method on the controller
        if (isset($attributes['method'])) {
            $controller .= ':'.$attributes['method'];
        }

        return $controller;
    }
protected function getControllerName(Reference $reference, array $attributes): string
    {
        $controller = (string) $reference;

        // Support a specific method on the controller
        if (isset($attributes['method'])) {
            $controller .= ':'.$attributes['method'];
        }

        return $controller;
    }
Returns the controller name from the service and method name.