social/mail_tracking_mailgun/views/res_partner.xml

<?xml version="1.0" encoding="utf-8" ?>
<!-- Copyright 2016 Tecnativa - Pedro M. Baeza
     Copyright 2016 Carlos Dauden - Tecnativa <carlos.dauden@tecnativa.com>
     Copyright 2017 Tecnativa <vicent.cubellsn@tecnativa.com>
     License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html). -->
<odoo>

    <record id="view_partner_form_mailgun" model="ir.ui.view">
        <field name="name">Partner Mailgun button</field>
        <field name="model">res.partner</field>
        <field name="inherit_id" ref="mail_tracking.view_partner_form" />
        <field name="arch" type="xml">
            <field name="email_bounced" position="after">
                <label
                    for="check_email_bounced"
                    string="Mailgun"
                    attrs="{'invisible': [('email', '=', False)]}"
                />
                <div
                    name="mailgun_buttons"
                    attrs="{'invisible': [('email', '=', False)]}"
                >
                    <button
                        name="check_email_bounced"
                        type="object"
                        string="Check Mailgun"
                        class="oe_link"
                    />
                    <button
                        name="check_email_validity"
                        type="object"
                        string="Check email validity"
                        class="oe_link"
                    />
                    <button
                        name="force_set_bounced"
                        type="object"
                        string="Set Bounced"
                        class="oe_link"
                        attrs="{'invisible': [('email_bounced', '=', True)]}"
                    />
                    <button
                        name="force_unset_bounced"
                        type="object"
                        string="Unset Bounced"
                        class="oe_link"
                        attrs="{'invisible': [('email_bounced', '=', False)]}"
                    />
                </div>
            </field>
        </field>
    </record>

</odoo>