protocol/xserver.xml

<protocol name="xserver">

  <interface name="xserver" version="1">
    <request name="set_window_id">
      <arg name="surface" type="object" interface="wl_surface"/>
      <arg name="id" type="uint"/>
    </request>

    <event name="client">
      <arg name="fd" type="fd"/>
    </event>

    <event name="listen_socket">
      <arg name="fd" type="fd"/>
    </event>
  </interface>

</protocol>