pos/pos_timeout/views/templates.xml

<?xml version="1.0" encoding="utf-8" ?>
<odoo>
    <template id="assets" name="pos_timeout assets" inherit_id="point_of_sale.assets">
        <xpath expr="." position="inside">
            <script
                type="text/javascript"
                src="/pos_timeout/static/src/js/pos_timeout.js"
            />
        </xpath>
    </template>
</odoo>