It sounds like Nintendo might not be exhibiting at E3 this year! It's hard to know for sure as Microsoft isn't on that list but has already confirmed that they'll be attending, so this might just be a clerical error, but I guess we'll know shortly. Also of note:
Attendees to this year's event might also be a bit concerned with security. In August, it came to light that the ESA, which organises E3, leaked the personal information of 2,000 industry professionals, which included home phone numbers and addresses.
The leak of the official website isn't quite at the same level—it's all going to be public information tomorrow—but it also suggests that the ESA still isn't very good at keeping details under wraps. To find the link to the WebOps platform that hosts the site, all you need to do is inspect the E3 logo.
Also Keighley just kind of said Nah to the whole thing:
I wanted to share some important news about my plans around E3 2020. pic.twitter.com/EhrreKV9oR— Geoff Keighley (@geoffkeighley) February 12, 2020