oca-technical/odoo-bringout-oca-hr-hr_employee_age/hr_employee_age/views/hr_employee.xml

<?xml version="1.0" encoding="utf-8" ?>
<odoo>
    <record id="hr_employee_view_form" model="ir.ui.view">
        <field name="name">hr.employee.view.form</field>
        <field name="model">hr.employee</field>
        <field name="inherit_id" ref="hr.view_employee_form" />
        <field name="arch" type="xml">
            <field name="birthday" position="after">
                <field name="age" />
            </field>
        </field>
    </record>
</odoo>