social/mass_mailing_custom_unsubscribe/views/mail_mass_mailing_list_view.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- © 2016 Pedro M. Baeza <pedro.baeza@tecnativa.com>
     License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl). -->

<openerp>
<data>

    <record id="view_mail_mass_mailing_list_form" model="ir.ui.view">
        <field name="model">mail.mass_mailing.list</field>
        <field name="inherit_id" ref="mass_mailing.view_mail_mass_mailing_list_form"/>
        <field name="arch" type="xml">
            <div class="oe_title" position="after">
                <group>
                    <field name="not_cross_unsubscriptable"/>
                </group>
            </div>
        </field>
    </record>

</data>
</openerp>