¿Por qué JDownloader usa 9666 / tcp en localhost?

Encontré 9666 / tcp para escuchar el 127.0.0.1 en OS X. Uso la versión 15.3.0

> nmap -sT 127.0.0.1                                                                                                                                      
Starting Nmap 7.01 ( https://nmap.org ) at 2016-03-12 16:57 CET
Stats: 0:00:04 elapsed; 0 hosts completed (1 up), 1 undergoing Connect Scan
Connect Scan Timing: About 56.90% done; ETC: 16:57 (0:00:03 remaining)
Nmap scan report for localhost (127.0.0.1)
Host is up (0.29s latency).
Not shown: 999 closed ports
PORT     STATE SERVICE
9666/tcp open  unknown

Nmap done: 1 IP address (1 host up) scanned in 8.31 seconds

> lsof -i :9666
    COMMAND     PID USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
    JavaAppli 73246 leo  149u  IPv4 0x49ece38ad86e34a7      0t0  TCP localhost:9666 (LISTEN)
> ps -ef | grep -w 73246
  503 73246     1   0  5:07PM ??        16:23.64 /Users/leo/Applications/JDownloader 2/JDownloader2.app/Contents/MacOS/JavaApplicationStub -afterupdate

¿Qué es eso? ¿Más detalles? Con Google no encontré información sobre este puerto y Jdownloader.