odoo16/addons/mass_mailing/views/mailing_contact_subscription_views.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <record model="ir.ui.view" id="mailing_contact_subscription_view_form">
        <field name="name">mailing.contact.subscription.view.form</field>
        <field name="model">mailing.contact.subscription</field>
        <field name="priority">10</field>
        <field name="arch" type="xml">
            <form string="Mailing List Subscription">
                <sheet>
                    <group>
                        <field name="list_id"/>
                        <field name="is_blacklisted" invisible="1"/>
                        <label for="contact_id" class="oe_inline"/>
                        <div class="o_row o_row_readonly">
                            <i class="fa fa-ban text-danger" role="img" title="This email is blacklisted for mass mailings"
                                aria-label="Blacklisted" attrs="{'invisible': [('is_blacklisted', '=', False)]}" groups="base.group_user"></i>
                            <field name="contact_id"/>
                        </div>
                        <field name="unsubscription_date" readonly="1"/>
                        <field name="opt_out"/>
                        <field name="message_bounce" readonly="1"/>
                    </group>
                </sheet>
            </form>
        </field>
    </record>

    <record model="ir.ui.view" id="mailing_contact_subscription_view_tree">
        <field name="name">mailing.contact.subscription.view.tree</field>
        <field name="model">mailing.contact.subscription</field>
        <field name="arch" type="xml">
            <tree string="Mailing List Subscriptions">
                <field name="contact_id"/>
                <field name="unsubscription_date"/>
                <field name="opt_out"/>
                <field name="message_bounce"/>
                <field name="is_blacklisted"/>
            </tree>
        </field>
    </record>

    <record model="ir.ui.view" id="mailing_contact_subscription_view_search">
        <field name="name">mailing.contact.subscription.view.search</field>
        <field name="model">mailing.contact.subscription</field>
        <field name="arch" type="xml">
           <search string="Mailing List Subscriptions">
                <field name="contact_id"/>
                <field name="opt_out"/>
                <field name="list_id"/>
            </search>
        </field>
    </record>
</odoo>