Maybe it is stored temporarily on the server to allow resumption of reviews (and broadcasts?) when there is a need to close the program or chance computers?
GoPanda2 has rather good review features but at least the following shortcomings:
1 It doesn't appear to be possible to safe to a file and reopen later.
2 Often when I try to add variations it doesn't add a variation, instead it jumps to the point in the game when that move was played.
3 It always shows the next move, which is annoying if you haven't seen the game before and would like to think what the next move is.
#1 there makes it rather useless for keeping notes but sometimes less is better
Btw
GoWrite2 is good for keeping notes.