muk_web/muk_web_branding/template/layout.xml

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

<!--     
	Copyright (C) 2017 MuK IT GmbH
	
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as
    published by the Free Software Foundation, either version 3 of the
    License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>. 
-->

<odoo>
	<template id="web_layout" inherit_id="web.layout">
       <xpath expr="//title" position="replace">
       		<title t-esc="title" />
       </xpath>
       <xpath expr="//link[@rel='shortcut icon']" position="before">
            <t t-if="not website">
                <t t-set="x_icon" t-value="'/web/binary/company_favicon'"/>
            </t>
        </xpath>
    </template>
</odoo>