File: /home/petsclubcc/magento/vendor/magento/module-theme/etc/adminhtml/system.xml
<?xml version="1.0"?>
<!--
/**
* Copyright © 2016 Magento. 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="design">
<group id="search_engine_robots" translate="label" type="text" sortOrder="25" showInDefault="1" showInWebsite="1" showInStore="1">
<label>Search Engine Robots</label>
<field id="default_robots" translate="label comment" type="select" sortOrder="40" showInDefault="1" showInWebsite="1" showInStore="1" canRestore="1">
<label>Default Robots</label>
<comment>This will be included before head closing tag in page HTML.</comment>
<source_model>Magento\Config\Model\Config\Source\Design\Robots</source_model>
</field>
<field id="custom_instructions" translate="label comment" type="textarea" sortOrder="70" showInDefault="1" showInWebsite="1" showInStore="1">
<label>Edit custom instruction of robots.txt File</label>
<backend_model>Magento\Config\Model\Config\Backend\Admin\Robots</backend_model>
</field>
<field id="reset_to_defaults" translate="label comment" type="button" sortOrder="80" showInDefault="1" showInWebsite="1" showInStore="1">
<label>Reset to Defaults</label>
<frontend_model>Magento\Backend\Block\Page\System\Config\Robots\Reset</frontend_model>
<comment>This action will delete your custom instructions and reset robots.txt file to system's default settings.</comment>
</field>
</group>
</section>
</system>
</config>