example-ui-file.ui

<?xml version='1.0' encoding='UTF-8'?>
<!-- Created with Cambalache 0.12.1 -->
<interface>
  <!-- interface-name hellobuilder.ui -->
  <requires lib="gtk" version="4.10"/>
  <object class="GtkApplicationWindow" id="window">
    <property name="title">UI File Example</property>
    <child>
      <object class="GtkBox">
        <property name="orientation">vertical</property>
        <child>
          <object class="GtkLabel" id="label">
            <property name="height-request">50</property>
            <property name="label">&lt;i&gt;Hello&lt;/i&gt; &lt;b&gt;World&lt;/b&gt;!</property>
            <property name="use-markup">True</property>
            <property name="vexpand">True</property>
            <property name="width-request">100</property>
          </object>
        </child>
        <child>
          <object class="GtkButton" id="button-exit">
            <property name="label">Exit</property>
          </object>
        </child>
      </object>
    </child>
  </object>
</interface>