This design feature never made it to the final version of the Apple Watch Ultra 1 released last September, as we now know, with the company instead opting for the light grey ceramic underside (shown below).
However, we do at least have an insight into what a darker version of the device would look like - and it's similar to what we've seen Apple release on its other smartwatches, like the Watch Series 9 and Watch SE 2.
In the filing, the orange Action button seems to be quite different from the final model, too, perhaps being made of plastic rather than the metal we've seen on both generations of the Ultra.
What's not known from the file is just how far back these images date, which, in turn, means it's difficult to know just when the decision was made to switch to a lighter color on the back.
With FCC filing details often confidentially held for quite a while before becoming available to the public, too, these kinds of images can take months - or years - to emerge.
And, interestingly, though Apple stuck with the grey ceramic for the Watch Ultra 2, there is a small chance this canceled design could be revived for a darker case in the future.
This was something that was strongly suggested would arrive when Apple announced the second-gen model in September, but it never actually materialized.
Is it possible we'll eventually see it pop up in a similar fashion to this later down the line? Only time will tell.
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