basically, there was a post made on a board a couple days ago that said "Come back on the 7th." and had a list of things regarding E3 for Nintendo. The first being "Nintendo will announce Online details on the 7th."
Low and behold, details for Switch Online came out on the 7th in America. I have seen a lot of people saying "OH LUCKY GUESS" and "WELL ANYONE COULD PREDICT IT", but it's pretty suspect that it came true.
Though on the other hand, some of the other things listed were a little far-fetched... like Waluigi DLC for Mario Odyssey. But who knows. Red/Blue reboot for switch is something I wanted, but I'd also love to have a new region based on something we haven't seen.