[Jason had planted a tracker on Bruce during their fight. How could he not? Jason knows this younger version of his adoptive father is going to keep being Batman and eventually he's going to cross paths with the Joker, assuming the psycho is still around. Bruce is obsessed. The whole family is to some degree.

Plus, Jason wants to keep pushing Bruce's boundaries and keep testing him. The man is younger and not as experienced as the Bruce Wayne Jason knows back home. There are weaknesses he hasn't worked out yet. Flaws in the metaphorical and literal armor. Jason wants to know.

Jason's been tailing Bruce for a while today and waiting to see if he'll be noticed. Closer and closer he gets and he keeps observing. Older Dick wasn't kidding that this is Bruce in an emo phase, even without the greasepaint around the eyes.

Soon enough Jason's within earshot of Bruce and he hears the man's comments]

Yeah. He's a real piece of work.

[Jason doesn't hide his Gothamite accent. It's not posh like one would have if they were raised rich. Instead, it's an accent that suggests he has a rougher livelihood. He waits to see how much information Bruce has already picked up and his opinion of the guilds]