https://www.pcgamer.com/borderlands-3-secret-message-hints-at-the-return-of-the-destroyer/

A hidden message has been discovered in the offline screen of the Borderlands Twitch channel that teases some potentially big revelations that might be coming in Borderlands 3. Discovered by YouTuber Joltzdude139, the messages—in Morse code—ask two questions drawn from Borderlands lore that could be very pertinent to long-time lore hunters. 

The code can only be seen in the image that's displayed when the Borderlands Twitch channel is offline, not in the otherwise-identical header art at the top of the page, and it's very faint and easy to overlook. There are two strings of dots and dashes, one on the left side of the Psycho, and one on the right: The message on the left translates to, "Where is the first vault hunter?" while the one on the right is, "Who is the Destroyer?"