What else would she be holding that mask for?
Zelda Williams has had an interesting presence at E3 2014, and given her namesake it's not surprising to see her hanging around. But regarding her "extra special" surprise at E3 that we touched upon late in May, she may have just given it away while appearing at the Super Smash Bros. Invitational tournament.
Zelda held a large Majora's Mask prop when she came out on stage for the Celebrity match, showing it off and making sure it was in full view for everyone at the tournament. Why make such a fuss about a specific prop? Why Majora's Mask? There's a big announcement about a 3DS game later today as well, and all the puzzle pieces fit together for a hopeful The Legend of Zelda: Majora's Mask 3DS reveal.
If not Majora's Mask, what do you think Zelda's surprise could be?
E3 2014: Did Zelda Williams Just Tease Majora's Mask 3D? [NintendoLife]