pos/pos_payment_terminal/views/assets.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>

    <template id="assets" inherit_id="point_of_sale.assets">
        <xpath expr="." position="inside">
            <script type="text/javascript" src="/pos_payment_terminal/static/src/js/screens.js"></script>
            <script type="text/javascript" src="/pos_payment_terminal/static/src/js/models.js"></script>
            <script type="text/javascript" src="/pos_payment_terminal/static/src/js/devices.js"></script>
            <link rel="stylesheet" href="/pos_payment_terminal/static/src/css/pos_payment_terminal.css" />
      </xpath>
    </template>

</odoo>