magento-test/app/code/Magento/Downloadable/etc/adminhtml/system.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
    <system>
        <section id="catalog">
            <group id="downloadable" translate="label" type="text" sortOrder="600" showInDefault="1" showInWebsite="1" showInStore="1">
                <label>Downloadable Product Options</label>
                <field id="order_item_status" translate="label" type="select" sortOrder="100" showInDefault="1" showInWebsite="1" canRestore="1">
                    <label>Order Item Status to Enable Downloads</label>
                    <source_model>Magento\Downloadable\Model\System\Config\Source\Orderitemstatus</source_model>
                </field>
                <field id="downloads_number" translate="label" type="text" sortOrder="200" showInDefault="1" showInWebsite="1" canRestore="1">
                    <label>Default Maximum Number of Downloads</label>
                    <validate>validate-digits validate-zero-or-greater</validate>
                </field>
                <field id="shareable" translate="label" type="select" sortOrder="300" showInDefault="1" showInWebsite="1" canRestore="1">
                    <label>Shareable</label>
                    <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
                </field>
                <field id="samples_title" translate="label" type="text" sortOrder="400" showInDefault="1" showInWebsite="1" showInStore="1" canRestore="1">
                    <label>Default Sample Title</label>
                </field>
                <field id="links_title" translate="label" type="text" sortOrder="500" showInDefault="1" showInWebsite="1" showInStore="1" canRestore="1">
                    <label>Default Link Title</label>
                </field>
                <field id="links_target_new_window" translate="label" type="select" sortOrder="600" showInDefault="1" showInWebsite="1" canRestore="1">
                    <label>Open Links in New Window</label>
                    <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
                </field>
                <field id="content_disposition" translate="label" type="select" sortOrder="700" showInDefault="1" showInWebsite="1" showInStore="1" canRestore="1">
                    <label>Use Content-Disposition</label>
                    <source_model>Magento\Downloadable\Model\System\Config\Source\Contentdisposition</source_model>
                </field>
                <field id="disable_guest_checkout" translate="label comment" type="select" sortOrder="800" showInDefault="1" showInWebsite="1" canRestore="1">
                    <label>Disable Guest Checkout if Cart Contains Downloadable Items</label>
                    <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
                    <comment>Guest checkout will only work with shareable.</comment>
                </field>
            </group>
        </section>
    </system>
</config>