A couple months ago, Universal Orlando Resort officially announced what had been rumored for well over a year, a third gate was on the way. The new theme park was to be called Epic Universe, but beyond the name, and some concept art, little was revealed about the park itself. It seems Universal really doesn't want any details getting out about Epic Universe, as the resort has actually gotten Orlando municipal workers to sign non-disclosure agreements regarding it.
According to the Orlando Sentinel, several Orlando Utility Commission workers were required to sign NDAs before they were allowed to begin working on the new project. While it's certainly standard practice for employees and independent contractors to sign documents like that before going to work, there's some significant question as to how legal it is to have city workers do the same, since there are laws requiring public disclosures at the municipal level.
The Orlando Utilities Commission provides electrical and water services, and so is obviously going to be key to the infrastructure of Epic Universe. It's also possible, that in designing how those services will need to be handled, workers will learn details of the park itself, including potentially, what sorts of attractions will be part of Epic Universe, and the park is not ready to release any of those details yet.
It may be that not all of the contracts have been finalized, so there are things that can't be announced, or it could just be that Universal wants to keep competition (read: Disney) in the dark as long as possible about what is being planned. Universal changed the theme park game when it revealed The Wizarding World of Harry Potter, and if the park has something that big in mind for Epic Universe, the longer it can keep it a secret, the longer it will take Disney to respond.
While the question of how legal it was to have public employees sign NDAs is one for somebody else, it certainly does show just how far Universal Orlando is going to keep Epic Universe secret.
This may be because the existence of Epic Universe itself was largely anything but secret. Rumors of a third Universal park had been around for some time and they were becoming so consistent that they almost had to be true. When Universal Orlando scheduled a big announcement, we all knew what it was.
None of the properties that will be used to theme the lands and attractions have been announced, though at least one of them is all but confirmed. Universal and Nintendo entered into an agreement to work on theme park attractions together years ago. Originally, the reported plan was for a new land to be added to one of the existing Universal Orlando parks. The fact that no work has ever been started would seem to strongly indicate that a Nintendo themed area is slated for the new park.
Another area that has been rumored for the new park is one dedicated to Star Trek.
How long Universal needs to keep these secrets is anybody's guess. No construction schedule has been announced so we don't know when this new park is looking to open. Expect details of the new park to be drip fed to fans over the next several years.