social/mail_digest/views/user_notification_views.xml

<?xml version="1.0"?>
<odoo>

    <record model="ir.ui.view" id="notification_form">
        <field name="name">user.notification.conf form</field>
        <field name="model">user.notification.conf</field>
        <field name="arch" type="xml">
            <form string="Notification">
                <group name="main">
                    <field name="enabled" />
                    <field name="subtype_id" options="{'no_create': True}" />
                </group>
            </form>
        </field>
    </record>

    <record model="ir.ui.view" id="notification_tree">
        <field name="name">user.notification.conf tree</field>
        <field name="model">user.notification.conf</field>
        <field name="arch" type="xml">
            <tree string="Notifications" editable="top">
                <field name="enabled" />
                <field name="subtype_id" />
            </tree>
        </field>
    </record>

</odoo>