china_addons/oec_theme_backend/data/res_company_data.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <data noupdate="0">

        <record id="base.main_company" model="res.company">
            <field name="logo" type="base64" file="oec_theme_backend/static/img/logo.png"/>
            <field name="square_logo" type="base64" file="oec_theme_backend/static/img/favicon.png"/>
            <field name="favicon" model="res.company" eval="obj()._get_theme_favicon(original=True)"/>
        </record>

    </data>
</odoo>