app-odoo/app_odoo_customize/views/app_odoo_customize_view.xml

<?xml version="1.0" encoding="UTF-8"?>
<odoo>
    <data>
        <template id="switch_language" name="switch_language assets" inherit_id="web.assets_backend">
            <xpath expr="." position="inside">
                <link rel="stylesheet" href="/app_odoo_customize/static/src/css/app.css"/>
                <script type="text/javascript" src="/app_odoo_customize/static/src/js/app_window_title.js"/>
                <script type="text/javascript" src="/app_odoo_customize/static/src/js/customize_user_menu.js"></script>
            </xpath>
        </template>
        <!-- some odoo version not support, please remove this if you are using odoo9 -->
        <!--<template id="replace_login" name="Login Layout" inherit_id="web.login_layout">-->
            <!--<xpath expr="//a[@target='_blank']" position="replace">-->
                <!--<a href="https://www.sunpop.cn" target="_blank">Powered by <span>odooApp</span></a>-->
            <!--</xpath>-->
        <!--</template>-->
    </data>
</odoo>