magento-test/app/code/Magento/Config/etc/db_schema.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<schema xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:framework:Setup/Declaration/Schema/etc/schema.xsd">
    <table name="core_config_data" resource="default" engine="innodb" comment="Config Data">
        <column xsi:type="int" name="config_id" unsigned="true" nullable="false" identity="true"
                comment="Config ID"/>
        <column xsi:type="varchar" name="scope" nullable="false" length="8" default="default" comment="Config Scope"/>
        <column xsi:type="int" name="scope_id" unsigned="false" nullable="false" identity="false"
                default="0" comment="Config Scope ID"/>
        <column xsi:type="varchar" name="path" nullable="false" length="255" default="general" comment="Config Path"/>
        <column xsi:type="text" name="value" nullable="true" comment="Config Value"/>
        <column xsi:type="timestamp" name="updated_at" on_update="true" nullable="false" default="CURRENT_TIMESTAMP"
                comment="Updated At"/>
        <constraint xsi:type="primary" referenceId="PRIMARY">
            <column name="config_id"/>
        </constraint>
        <constraint xsi:type="unique" referenceId="CORE_CONFIG_DATA_SCOPE_SCOPE_ID_PATH">
            <column name="scope"/>
            <column name="scope_id"/>
            <column name="path"/>
        </constraint>
    </table>
</schema>