<interface>
    <object class="GtkNotebook" id="mynotebook">
      <child>
        <object class="GtkLabel" id="notebook-content">
          <property name="label">Content</property>
        </object>
      </child>
      <child type="tab">
        <object class="GtkLabel" id="notebook-tab">
          <property name="label">Tab</property>
        </object>
      </child>
    </object>
</interface>