<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Api/etc/extension_attributes.xsd">
    <extension_attributes for="Magento\Sales\Api\Data\OrderInterface" >
        <attribute code="facebook_order_id" type="string" />
        <attribute code="channel" type="string" />
        <attribute code="email_remarketing_option" type="string" />
    </extension_attributes>
</config>
