flectra/addons/crm_phone_validation/views/res_config_settings_views.xml

<?xml version="1.0" encoding="UTF-8" ?>
<flectra>
    <record id="res_config_settings_view_form" model="ir.ui.view">
        <field name="name">res.config.settings.view.form.inherit.crm.phone.validation</field>
        <field name="model">res.config.settings</field>
        <field name="inherit_id" ref="crm.res_config_settings_view_form" />
        <field name="arch" type="xml">
            <xpath expr="//div[@id='module_crm_phone_validation']" position="after">
                <div class="content-group">
                    <div class="mt16" attrs="{'invisible': [('module_crm_phone_validation','=',False)]}">
                        <label for="crm_phone_valid_method" class="o_light_label"/>
                        <field name="crm_phone_valid_method" widget="radio" class="o_light_label"/>
                    </div>
                </div>
             </xpath>
        </field>
    </record>
</flectra>