oca-ocb-core/odoo-bringout-oca-ocb-mail/mail/data/mail_templates_invite.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <data>
        <template id="mail_notification_invite" inherit_id="mail.mail_notification_layout" primary="True">
            <xpath expr="//td[@t-if='subtitles']" position="before">
                <t t-if="not has_button_access">
                    <t t-set="subtitles" t-value="False" />
                </t>
            </xpath>
            <xpath expr="//div[@t-out='message.body']" position="replace">
                <div style="font-size:13px;">
                    <div class="o-mail-invite-openingMessage">
                        <t t-out='message.author_id.name'/> (<t t-out='message.author_id.email'/>) added you as a follower of this <t t-out="model_description"/>.
                    </div>
                    <br t-if="len(message.body) > 0"/>
                    <div style="color:grey;">
                        <t t-out="message.body"/>
                    </div>
                </div>
            </xpath>
            <xpath expr="//span[@id='mail_unfollow']" position="replace"/>
            <xpath expr="//div[@style='margin-top:16px;']/hr" position="before">
                <span t-if="show_unfollow" id="mail_unfollow" style="font-size: 13px;">
                    Not interested by this? <a href="/mail/unfollow" style="text-decoration:none; color:#555555;">Unfollow</a>
                </span>
            </xpath>
        </template>

        <template id="mail_notification_multi_invite" inherit_id="mail.mail_notification_invite" primary="True">
            <xpath expr="//div[hasclass('o-mail-invite-openingMessage')]" position="replace">
                <div>
                    <t t-out='message.author_id.name'/> (<t t-out='message.author_id.email'/>) added you as a follower of <t t-out="model_description"/> listed below:
                </div>
            </xpath>
        </template>
    </data>
</odoo>