This is being marketed the same way the "Bonus Scene" on the WW home release was. So I doubt its A) being put back into the movie or B) being called a "deleted scene." By making these scenes "Bonus Scenes" they don't give us a re-edited movie, but (IMO) make these scenes a part of the canon, unlike deleted scenes which aren't. My guess? Its a cut scene involving Aquaman that sets up his solo film ala "bonus scene epilogue" on WW blu-ray setting up JL.
Also for all of those "I told you there was no extended/Snyder cut coming" - If either of those cuts were ever going to see the light of day, it would NOT have been with this initial release. BVS was a different story as that cut was completely finished, and I'd argue that(most likely) the stuff put back into SS was probably the very last stuff cut, very late in the game, so the additional footage was already mastered and scored. With JL, its a different story. We know that only the final theatrical cut was what Elfman scored, and soon as Whedon came aboard his directive was the make a 2 hour film. So they would have to go back and re-edit and finish FX and score in either instance. I'm not saying with any certainty at all that we are going to get a different cut in the future, but the fact is a 100% completed alternate/extended cut does not exist...yet. That combined with all the leadership changes that juuuust happened, means there was no way a re-edit was going to happen this soon. Now Emmerich and Hamada could be discussing a future extended cut today for all we know, but they were just appointed in their new roles.
