server-ux/base_tier_validation_forward/data/mail_data.xml

<?xml version="1.0" encoding="utf-8" ?>
<flectra noupdate="1">
    <record
        id="mt_tier_validation_forwarded"
        model="mail.message.subtype"
        forcecreate="1"
    >
        <field name="name">Tier Validation Forward Notification</field>
        <field name="default" eval="True" />
        <field name="internal" eval="True" />
        <field name="hidden" eval="True" />
    </record>
</flectra>