instant-epp/tests/resources/request/extensions/namestore.xml

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
    <command>
        <check>
            <check xmlns="urn:ietf:params:xml:ns:domain-1.0">
                <name>example1.com</name>
                <name>example2.com</name>
                <name>example3.com</name>
            </check>
        </check>
        <extension>
            <namestoreExt xmlns="http://www.verisign-grs.com/epp/namestoreExt-1.1">
                <subProduct>com</subProduct>
            </namestoreExt>
        </extension>
        <clTRID>cltrid:1626454866</clTRID>
    </command>
</epp>