https://www.pcgamer.com/borderlands-3-fans-think-theyve-found-the-release-date-in-the-trailer/

The Borderlands "Mask of Mayhem" teaser was filled with references, Easter eggs, and other half-hidden bits of information. Some of it was simple, like images of popular characters that will presumably be back for the new game, but other stuff, including broken-up shift codes, morse code, and even braille, was really well-buried. It was a veritable cornucopia of references. Would we expect any less from the full Borderlands 3 reveal trailer? 

We've got a rundown of everything we learned from the trailer here, but one thing that eluded our eyes was caught by redditor Zottelpanda, who has put together a pretty convincing argument that the release date is stashed away in there, too.