opnsense-plugins/net-mgmt/zabbix-proxy/src/opnsense/mvc/app/models/OPNsense/Zabbixproxy/Menu/Menu.xml

<menu>
  <Services>
    <Zabbixproxy VisibleName="Zabbix Proxy" cssClass="fa fa-eye" url="/ui/zabbixproxy/general/index" />
  </Services>
</menu>