Odoo-Build/snippets/stock.report_delivery_document.get_position2.xml

<data inherit_id="stock.report_delivery_document" priority="60">

    <xpath expr="//table[@name='stock_move_line_table']/thead/tr/th[1]" position="before">
        <th id="position" class="text-start">
            <strong>Pos.</strong>
        </th>
    </xpath>
    <xpath expr="//table[@name='stock_backorder_table']/thead/tr/th[1]" position="before">
        <th id="position" class="text-start">
            <strong>Pos.</strong>
        </th>
    </xpath>

</data>