When the trial begins the first thing we can find is a man standing in the top left, behind the jury. He doesn't show up in the cutscene, and apparently serves no further purpose. He's just someone who is there.

   

In the room just north of the torture chamber we can see Lucca standing outside the door. However, once you fight off the Decedents, she changes to the text "Miss89". Obviously, Lucca's sprite is there so she can burst through the door and save you if you wait to be executed. I'm baffled as to why she changes to text if you fight, though.

Just because I haven't shown it for a while, here's our mystery bubbly background again, this time making its appearence after our heroes teleport to Bangor Dome. It was at this point that I came up with a theory as to what this background means: a theory which can be found on the theories page.

Unfortunately that's it for this part of the game. 2300AD is very tidy compared to the rest of the game, and the only things I can find to show are things that have already been shown.