flectra/addons/website_mass_mailing/views/res_config_settings_views.xml

<?xml version="1.0" encoding="utf-8"?>
<flectra>
    <record id="res_config_settings_view_form" model="ir.ui.view">
        <field name="inherit_id" ref="mass_mailing.res_config_settings_view_form"/>
        <field name="name">res.config.settings.view.form.inherit.website.mass.mailing</field>
        <field name="model">res.config.settings</field>
        <field name="arch" type="xml">
            <xpath expr="//div[@id='mailing_list']" position="inside">
                <div class="col-md-6 o_setting_box col-xs-12" title="This adds a new Newsletter Popup snippet to drag &amp; drop on on your website pages. It triggers a popup when visitors land on the page. This popup prompts them to enter their email address to join a mailing list.">
                    <div class="o_setting_left_pane">
                        <field name="group_website_popup_on_exit"/>
                    </div>
                    <div class="o_setting_right_pane">
                        <label for="group_website_popup_on_exit"/>
                        <div class="text-muted">
                            Encourage to subscribe to mailing lists with a popup
                        </div>
                    </div>
                </div>
            </xpath>
        </field>
    </record>
</flectra>