It's not yet famous enough to know. The only way to answer is to find out how people who know it, say it. I suggest you sent an email to firstname.lastname@example.org and ask them.
Like me, native English speakers who don't know will guess, and my first guess would be to use the name of the letter "x" (i.e. "ex.") My second guess would be the word "by," because expressions like 8x10 are read as "eight by ten." When trying to communicate with other English speakers I would say "ex," but I would be ready to have someone correct me.