social/mail_digest/views/mail_digest_views.xml

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

    <record model="ir.ui.view" id="mail_digest_tree">
        <field name="name">mail_digest mail.digest.tree</field>
        <field name="model">mail.digest</field>
        <field name="arch" type="xml">
            <tree string="Mail digest">
                <field name="user_id" />
                <field name="mail_id" />
                <field name="state" />
            </tree>
        </field>
    </record>


    <record model="ir.ui.view" id="mail_digest_form">
        <field name="name">mail_digest mail.digest.form</field>
        <field name="model">mail.digest</field>
        <field name="arch" type="xml">
            <form string="Mail digest">
                <sheet>
                    <div class="oe_button_box" name="button_box">
                        <button name="action_create_email" icon="fa-envelope"
                                string="Create email now"
                                type="object" attrs="{'invisible': [('mail_id', '!=', False)]}" />
                    </div>
                    <group name="main" col="2">
                        <field name="name" />
                        <field name="user_id" />
                    </group>
                    <group name="settings" col="2">
                        <field name="frequency" />
                        <field name="mail_id" />
                        <field name="state" />
                        <field name="digest_template_id" />
                    </group>
                    <group name="messages" string="Messages" col="4">
                        <field name="message_ids" nolabel="1" />
                    </group>
                </sheet>
            </form>
        </field>
    </record>

    <record model="ir.actions.act_window" id="action_digest_all">
        <field name="name">Digest</field>
        <field name="res_model">mail.digest</field>
        <field name="view_type">form</field>
        <field name="view_mode">form,tree</field>
        <field name="view_id" ref="mail_digest_tree" />
    </record>

    <menuitem id="menu_email_digest" parent="base.menu_email"
              action="action_digest_all"
              sequence="90"/>

</odoo>