flectra/addons/website_sale_digital/views/website_sale_digital.xml

<?xml version="1.0" encoding="utf-8"?>
<flectra>
    <template id="portal_order_page_downloads" name="Orders Downloads Followup" inherit_id="sale.portal_order_page">
        <xpath expr="//div[@id='product_name']" position="inside">
            <t t-set="attachments" t-value="digital_attachments.get(ol.product_id.id)"/>
            <t t-if="attachments">
                <span class="dropdown">
                    <button class="btn btn-xs btn-default dropdown-toggle" type="button" id="dropdownMenu1" data-toggle="dropdown">
                        Downloads <span class="caret"></span>
                    </button>
                    <ul class="dropdown-menu" role="menu" aria-labelledby="dropdownMenu1">
                        <t t-foreach="attachments" t-as="a">
                            <li role="presentation"><a role="menuitem" tabindex="-1" t-att-href="'/my/download?attachment_id=%i' % a['id']"><t t-esc="a['name']"/></a></li>
                        </t>
                    </ul>
                </span>
            </t>
        </xpath>
    </template>
</flectra>