I detailed the response format in a PM conversation with Tony. Maybe he can repost it here.

Here's the resulting notes I have from that conversation. I created a list of queries and the responses that my Jupiter returned when I tried...

(Get the list of playlists...)
http://192.168.0.4:12078/content/100?_extended=1

3760=P(Low Key)
3c80=P(Workout)
5620=Ptemp

(Get all the songs in one playlist...)
http://192.168.0.4:12078/content/3760?_extended=1

3ee0=TLessons
3ef0=TTears
3f30=TCloser to the Heart
3500=T'39
3520=TSeaside Rendezvous
(...)

(Play a FID once we know it...)
http://192.168.0.4:12078/content/3ee0

(Plays LESSONS)


http://192.168.0.4:12078/query?artist=a

matches=
0=0,0,0:Aaron Copland
1=0,0,0:Aimee Mann
2=0,0,0:Al Petteway
3=0,0,0:Al Petteway and Amy White
4=0,0,0:Alabama 3
(... all artists that start with a)

http://192.168.0.4:12078/query?artist=

matches=
0=0,0,0:10,000 Maniacs
1=0,0,0:Aaron Copland
2=0,0,0:Aimee Mann
3=0,0,0:Al Petteway
(... entire database is returned, by artist)


http://192.168.0.4:12078/results?artist=Rush

Gets a funky binary file named results.txt?


"You might need to stick '&_format=1' (or =2, or =3) on the
end of that to get the results in a different format.
Otherwise, I think it's just a binary list of FIDs (and
possibly lengths or something). Or, that might be '&_extended='.
I suggest that you download a copy of Ethereal and watch what a
real client does."

http://192.168.0.4:12078/results?artist=Rush&_extended=1

3eb0=T2112
5570=T2112- Discovery (Live DS)
7230=T2112- Oracle- The Dream (Live DS)
5550=T2112- Overture (Live DS)
5580=T2112- Presentation (Live DS)
(... all songs by Rush)


http://192.168.0.4:12078/results?source=2112&_extended=1

3eb0=T2112
3ec0=TA Passage to Bangkok
3ed0=TThe Twilight Zone
3ee0=TLessons
3ef0=TTears
3f00=TSomething for Nothing

(... the album 2112 in alphabetical order)