Odoo-Build/snippets/mint_system.stock.report_picking.show_default_code.xml

<data priority="50">
    <xpath expr="//th[@id='th_product']" position="before">
        <th id="default_code">
            <strong>Part No.</strong>
        </th>
    </xpath>
    <xpath expr="//td[@id='description_picking']" position="before">
        <td id="default_code">
            <span t-field="ml.product_id.default_code"/>
        </td>
    </xpath>
</data>