Though Batman v Superman: Dawn of Justice features plenty of Easter eggs and deep cut nods to the overarching DC lore, it also raises a fair number of other questions that still have yet to receive definitive answers. Chief among these is the subject of the Robin outfit in The Batcave, which many have assumed belongs to the now-deceased Jason Todd. Alas, despite that assumption, Zack Snyder doesn't want us getting too comfortable with that idea just yet. In response to fans asking about the possibility of a potential Jason Todd subplot cut from Dawn of Justice, Zack Snyder took to his Vero account and wrote:
what makes you think that's Jason Todd
Most fans previously assumed that the defiled Robin suit in The Batcave belonged to Jason Todd during his career as The Boy Wonder. The suit is a clear reference to the A Death in the Family story arc, in which The Joker beats him mercilessly with a crowbar and leaves him to die in an explosion. However, despite the fact that The Joker clearly had a hand in this Robin's death, Zack Snyder doesn't seem so sure of the fact that this truly is Jason Todd's outfit.
From there, that raises further questions about who the Robin suit actually belongs to. The odds of it belonging to Dick Grayson seem low, particularly when we consider the fact that a Nightwing movie is still in development. That said, that suit could also belong to Tim Drake or Damian Wayne, or even someone like Carrie Kelly. Robin is a mantle passed from sidekick to sidekick in the DC Comics pages, so it would only take some minor changes to pass the death off from Jason onto another Robin.
Of course, one thing that we specifically need to remember in this instance is that Zack Snyder might merely be toying with his fans with this Vero post. He's forcing us to question whether or not that Robin suit actually belongs to the second Boy Wonder, but he's also not denying that it does. He's undoubtedly planting seeds of doubt, but there's also plenty of room for him to circle back and admit this truly is Jason's outfit. In fact, after the release of Dawn of Justice in 2016, a Warner Bros. tour guide seemingly confirmed that the DCEU Robin is actually Jason, so at this point, it really comes down to what you choose to believe.