suite/hr_department_project/views/hr_views.xml

<?xml version="1.0" encoding="UTF-8" ?>
<odoo>
    <record model="ir.ui.view" id="view_department_form_inherited">
        <field name="name">hr.department.form.inherited</field>
        <field name="model">hr.department</field>
        <field name="inherit_id" ref="hr.view_department_form"/>
        <field name="arch" type="xml">
            <xpath expr="//widget[@name='web_ribbon']" position="before">
                <div class="oe_button_box" name="button_box">
                    <button class="oe_stat_button" name="project_tree_view" type="object" icon="fa-puzzle-piece">
                        <field string="Projects" name="project_count" widget="statinfo"/>
                    </button>
                </div>
            </xpath>
        </field>
    </record>
</odoo>