Because the film was shot on Super 35mm film, there is extra vertical image hidden above and below the widescreen theatrical bars. People find or make this version through specific avenues:
But here is the magic: Open Matte does not crop the original image. Instead, it adds picture information to the top and bottom of the frame. You see more of the set, more of the sky, and more of the actors’ bodies. watchmen 2009 directors cut open matte 1080 top
The version offers a fascinating trade-off: Because the film was shot on Super 35mm
This is subjective, but the consensus among Watchmen superfans is: more of the sky