reporting-engine/report_qweb_pdf_watermark/demo/report.xml

<?xml version="1.0" encoding="UTF-8"?>
<odoo>
    <report
        id="demo_report"
        string="Demo report"
        model="res.users"
        report_type="qweb-pdf"
        name="report_qweb_pdf_watermark.demo_report_view"
        file="report_qweb_pdf_watermark.demo_report_view"
        paperformat="report.paperformat_euro"
        />
    <record id="demo_report" model="ir.actions.report.xml">
        <field name="pdf_watermark_expression">docs[:1].company_id.logo</field>
    </record>
    <template id="demo_report_view">
        <t t-call="report.html_container">
            <t t-call="report.external_layout">
                <div class="page">
                    <ul>
                        <li t-foreach="docs" t-as="doc">
                            <t t-esc="doc.name" />
                        </li>
                    </ul>
                </div>
            </t>
        </t>
    </template>
</odoo>