reporting-engine/report_xlsx/views/webclient_templates.xml

<?xml version="1.0" encoding="UTF-8" ?>
<odoo>
    <!--
    © 2017 Creu Blanca
    License AGPL-3.0 or later (https://www.gnuorg/licenses/agpl.html).
    -->
    <template id="assets_backend" inherit_id="web.assets_backend">
        <xpath expr="." position="inside">
            <script type="text/javascript" src="/report_xlsx/static/src/js/report/action_manager_report.js"/>
        </xpath>

    </template>
</odoo>