partner-contact/base_location/views/res_country_view.xml

<?xml version="1.0" encoding="utf-8" ?>
<odoo>
    <record id="view_country_search" model="ir.ui.view">
        <field name="name">res.country.search</field>
        <field name="model">res.country</field>
        <field name="arch" type="xml">
            <search string="Country">
                <field name="name" />
                <field name="code" />
            </search>
        </field>
    </record>
    <record id="view_res_country_city_better_zip_form" model="ir.ui.view">
        <field name="model">res.country</field>
        <field name="inherit_id" ref="base.view_country_form" />
        <field name="arch" type="xml">
            <xpath expr="//div[hasclass('oe_button_box')]" position="inside">
                <button
                    name="%(action_zip_tree)d"
                    class="oe_stat_button"
                    icon="fa-globe"
                    type="action"
                    context="{'default_country_id': active_id, 'search_default_country_id': active_id}"
                    string="Zips"
                >

                </button>
            </xpath>
        </field>
    </record>
</odoo>