Tech hardware companies must share details with the FCC when launching new devices, and Apple does the same ahead of the release of Apple Watch Ultra in September 2022. Apple's original design of the Apple Watch Ultra appears to have had a dark ceramic back, according to filings with the FCC posted by @ParrotSWD on Twitter.
In this document, Apple appears to be using an Apple Watch Ultra, which has a darker, almost black ceramic back, similar to the Apple Watch Series models, and the action buttons appear to be plastic and not indented. These design features did not make it into the final version.
In such documents, exterior photos and other sensitive details are often subject to a non-disclosure clause that has an expiration date, so it is likely that this clause has recently expired and the images have been exposed.
The Apple Watch Ultra 2 currently offered by Apple will be released in September 2023 and uses the same natural titanium color as the first-generation model. Ahead of the launch, there were rumors that Apple might introduce a new dark color option, which was originally tested on the previous-generation model but ultimately canceled. But that didn't happen.