server-backend/base_user_effective_permissions/views/res_users.xml

<?xml version="1.0" encoding="utf-8" ?>
<!-- Copyright 2023 Hunki Enterprises BV
     License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl-3.0) -->
<data>
    <record id="view_users_form" model="ir.ui.view">
        <field name="model">res.users</field>
        <field name="inherit_id" ref="base.view_users_form" />
        <field name="arch" type="xml">
            <xpath expr="//div[@name='button_box']" position="inside">
                <button
                    name="action_show_effective_permissions"
                    type="object"
                    groups="base.group_no_one"
                    icon="fa-shield"
                ><span class="o_stat_text">Effective permissions</span></button>
            </xpath>
        </field>
    </record>
</data>