尊重 Magento 2 标准化的正确答案是重载 magento/Backend/etc/adminhtml 的 system.xml。你应该试试:Vendor/ModuleName/etc/adminhtml/system.xml
<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
<system>
<section id="general">
<group id="country" translate="label" type="text" sortOrder="1" showInDefault="1" showInWebsite="1" showInStore="1">
<label>Country Options</label>
<field id="allow" translate="label" type="multiselect" sortOrder="2" showInDefault="1" showInWebsite="1" showInStore="1" canRestore="1">
<label>Allow Countries</label>
<source_model>Magento\Directory\Model\Config\Source\Country</source_model>
<can_be_empty>1</can_be_empty>
</field>
</group>
</section>
</system>
</config>
记得添加覆盖模块 - Magento_Backend
供应商/模块名称/etc/module.xml
<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
<module name="Vendor_YourModule" setup_version="1.0.0">
<sequence>
<module name="Magento_Backend"/>
</sequence>
</module>
</config>