flectra/addons/event/wizard/event_confirm_view.xml

<?xml version="1.0" encoding="utf-8"?>
<flectra>
    <data>

        <record id="view_event_confirm" model="ir.ui.view">
            <field name="name">Event Confirmation</field>
            <field name="model">event.confirm</field>
            <field name="arch" type="xml">
              <form string="Event Confirmation">
                  <label string="Warning: This Event has not reached its Minimum Registration Limit. Are you sure you want to confirm it?"/>
                  <footer>
                      <button name="confirm" string="Confirm Anyway" type="object" class="btn-primary"/>
                      <button string="Cancel" class="btn-default" special="cancel" />
                  </footer>
            </form>
            </field>
        </record>

        <record id="action_event_confirm" model="ir.actions.act_window">
            <field name="name">Event Confirmation</field>
            <field name="type">ir.actions.act_window</field>
            <field name="res_model">event.confirm</field>
            <field name="view_type">form</field>
            <field name="view_mode">form</field>
            <field name="view_id" ref="view_event_confirm"/>
            <field name="context">{'record_id' : active_id}</field>
            <field name="target">new</field>
        </record>

    </data>
</flectra>