Here Captain Rex holds a copy of Star Trek Magazine while Bo-Katan holds a copy of Bride Magazine.
I'll sometimes use these kinds of props during my engagement session photography to help establish certain personality traits or interests of brides and grooms that might otherwise be difficult to pass along in a single photograph.
Here the magazines are automatically viewed as both ironic and satirical given the nature of the costume armor worn by Michael and Stacey. The satire is heightened given that Captain Rex is reading a Star Trek magazine even though he is a character from the Star Wars universe.
There's an even deeper level of irony here for knowledgeable geeks as there is a big rivalry between fans of Star Trek and Star Wars with ongoing arguments about which series is better.