server-tools/base_user_role/views/group.xml

<?xml version="1.0" ?>
<odoo>
    <record id="res_groups_view_form" model="ir.ui.view">
        <field name="name">res.groups.form - base_user_role</field>
        <field name="model">res.groups</field>
        <field name="inherit_id" ref="base.view_groups_form" />
        <field name="arch" type="xml">
            <xpath expr="//sheet/group" position="before">
                <div name="button_box" class="oe_button_box">
                    <button
                        class="oe_stat_button"
                        name="action_view_roles"
                        type="object"
                        icon="fa-gears"
                        attrs="{'invisible': [ ('role_count', '=', 0)]}"
                    >
                        <field string="Roles" name="role_count" widget="statinfo" />
                    </button>
                </div>
            </xpath>
        </field>
    </record>
</odoo>