web/web_switch_company_warning/static/src/xml/switch_company_warning.xml

<?xml version="1.0" encoding="UTF-8"?>
<template>
    <t t-name="web_switch_company_warning.warningWidget">
        <div class="container-fluid bg-warning" style="text-align: center; display:none;">
            <h3>You switched to a different company or database with another tab or window</h3>
            <p><button onclick="location.reload(true);" class="btn">Reload</button> to refresh your session</p>
        </div>
    </t>
</template>