When I first read this short story, I assumed that it was Anakin's lightsaber in the box, but after the dust has settled from TFA, I believe that it is most likely Vader's mask. The movie revealed that Maz came into possession of Anakin's lightsaber, and we still don't know that story yet. But it's clear after the fact that whatever is in the box is not the saber. Bazine was working for a mysterious client that the book alludes to possibly being Kylo Ren or some other dark side figure. She was clearly not retrieving the case for Maz in any case. The mask of Vader I think is the most likely answer to what was in the box given that it is the only other relic we see in TFA besides the saber.

Click to expand...