Magento app/config.xml showing custom data format factory for extensibility alpha-1

config.xml

<global>
    <webhook>
        <formats>
            <json>
                <label>My-JSON</label>
                <options>
                    <default_formatter>Mage_Webhook_Model_Formatter_Json</default_formatter>
                </options>
                <formatter_factory>MyCustomClass_Webhook_Model_Formatter_Factory_Json</formatter_factory>
            </json>
        </formats>
        <subscriber_id>
                <version>1.1</version>
                <format>My-JSON</format>
                <name>Test subscriber</name>
        ... portions omitted intentionally
        </subscriber_id>
    </webhook>
</global>