labwc/docs/menu.xml

<?xml version="1.0" encoding="UTF-8"?>

<openbox_menu>

<menu id="client-menu">
  <item label="Minimize">
    <action name="Iconify" />
  </item>
  <item label="Maximize">
    <action name="ToggleMaximize" />
  </item>
  <item label="Fullscreen">
    <action name="ToggleFullscreen" />
  </item>
  <item label="Decorations">
    <action name="ToggleDecorations" />
  </item>
  <item label="AlwaysOnTop">
    <action name="ToggleAlwaysOnTop" />
  </item>
  <menu id="workspaces" label="Workspace">
    <item label="Move left">
      <action name="SendToDesktop" to="left" />
      <action name="GoToDesktop" to="left" />
    </item>
    <item label="Move right">
      <action name="SendToDesktop" to="right" />
      <action name="GoToDesktop" to="right" />
    </item>
  </menu>
  <item label="Close">
    <action name="Close" />
  </item>
</menu>

<menu id="root-menu">
  <item label="Web browser">
    <action name="Execute" command="firefox" />
  </item>
  <item label="Terminal">
    <action name="Execute" command="alacritty" />
  </item>
  <item label="Reconfigure">
    <action name="Reconfigure" />
  </item>
  <item label="Exit">
    <action name="Exit" />
  </item>
  <item label="Poweroff">
    <action name="Execute" command="systemctl -i poweroff" />
  </item>
</menu>

<menu id="some-custom-menu">
  <item label="Reconfigure">
    <action name="Reconfigure" />
  </item>
  <item label="Exit">
    <action name="Exit" />
  </item>
</menu>

</openbox_menu>