muk_web/muk_web_theme/templates/webclient.xml

<?xml version="1.0" encoding="UTF-8"?>

<odoo>
	
	<template id="webclient_bootstrap" name="Web Client" inherit_id="web.webclient_bootstrap">
        <xpath expr="//t[@t-set='head']" position="after">
            <t t-set="head_web_theme">
                <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no"/>
            </t>
            <t t-set="head" t-value="head_web_theme + (head or '')"/>
        </xpath>
        <xpath expr="//t[@t-set='body_classname']" position="after">
        	<t t-set="body_sidebar_classname" t-value="'mk_sidebar_type_' + request.env.user.sidebar_type or 'small'"/>
            <t t-set="body_classname" t-value="'%s %s' % (body_classname, body_sidebar_classname)"/>
        </xpath>
    </template>
	
</odoo>