partner-contact/partner_multi_relation/views/res_partner.xml

<?xml version="1.0" encoding="UTF-8" ?>
<odoo>
    <record id="view_res_partner_filter" model="ir.ui.view">
        <field name="name">partner_multi_relation.view_partner_filter</field>
        <field name="inherit_id" ref="base.view_res_partner_filter" />
        <field name="model">res.partner</field>
        <field type="xml" name="arch">
            <field name="parent_id" position="after">
                <field name="search_relation_partner_id" />
                <field name="search_relation_type_id" />
                <field name="search_relation_date" />
                <field name="search_relation_partner_category_id" />
            </field>
        </field>
    </record>
    <record id="view_partner_form" model="ir.ui.view">
        <field name="name">partner_multi_relation.view_partner_form</field>
        <field name="inherit_id" ref="base.view_partner_form" />
        <field name="model">res.partner</field>
        <field type="xml" name="arch">
            <xpath expr="//div[@name='button_box']" position="inside">
                <button
                    name="action_view_relations"
                    type="object"
                    class="oe_stat_button"
                    icon="fa-users"
                >
                    <field name="relation_count" widget="statinfo" string="Relations" />
                </button>
            </xpath>
        </field>
    </record>
    <record id="action_show_partner_multi_relation" model="ir.actions.act_window">
        <field name="name">Show partner's relations</field>
        <field name="binding_model_id" ref="base.model_res_partner" />
        <field name="res_model">res.partner.relation.all</field>
        <field name="view_mode">tree,form</field>
        <field name="domain">[('this_partner_id', 'in', active_ids)]</field>
    </record>
</odoo>