Neos\Neos\Controller\Backend\ContentController::initializeAssetsWithMetadataAction PHP Method

    protected function initializeAssetsWithMetadataAction()
    {
        $propertyMappingConfiguration = $this->arguments->getArgument('assets')->getPropertyMappingConfiguration();
        $propertyMappingConfiguration->allowAllProperties();
        $propertyMappingConfiguration->setTypeConverterOption(AssetInterfaceConverter::class, AssetInterfaceConverter::CONFIGURATION_OVERRIDE_TARGET_TYPE_ALLOWED, true);
        $propertyMappingConfiguration->forProperty('*')->setTypeConverterOption(AssetInterfaceConverter::class, AssetInterfaceConverter::CONFIGURATION_OVERRIDE_TARGET_TYPE_ALLOWED, true);
    }