Neos\Flow\Core\Booting\Scripts::initializeErrorHandling PHP Method

    public static function initializeErrorHandling(Bootstrap $bootstrap)
    {
        $configurationManager = $bootstrap->getEarlyInstance(ConfigurationManager::class);
        $settings = $configurationManager->getConfiguration(ConfigurationManager::CONFIGURATION_TYPE_SETTINGS, 'Neos.Flow');
        $errorHandler = new ErrorHandler();
        $errorHandler->setExceptionalErrors($settings['error']['errorHandler']['exceptionalErrors']);
        $exceptionHandler = new $settings['error']['exceptionHandler']['className']();
        $exceptionHandler->injectSystemLogger($bootstrap->getEarlyInstance(SystemLoggerInterface::class));
        $exceptionHandler->setOptions($settings['error']['exceptionHandler']);
    }