web/web_widget_url_listview/demo/demo.xml

<openerp>
    <data>
        <record id="demo_url_field" model="ir.ui.view">
            <field name="name">demo.url.field</field>
            <field name="model">ir.module.module</field>
            <field name="inherit_id" ref="base.module_tree"/>
            <field name="arch" type="xml">
                <xpath expr="//field[@name='author']" position="after">
                    <field name="website" widget="url"/>
                </xpath>
            </field>
        </record>
    </data>
</openerp>