Odoo-Build/snippets/mail.mail_notification_light.set_model_name.xml

<?xml version="1.0"?>
<data inherit_id="mail.mail_notification_light" priority="60">
    <xpath expr="//span[1]" position="replace">
        <span style="font-size: 10px;">
            <t t-esc="model_description or 'document'"/>
        </span>
        <br/>
    </xpath>
</data>