FCC
It was widely rumored before Apple launched the iPhone X that it would come in black, silver, and gold, but when the device went on sale, there were only black and silver options.
Now, photos published as part of a regulatory filing reveal that Apple did in fact make a gold version of the iPhone X.
These "external" photos are submitted to the FCC as part of a package to get regulatory approval to sell wireless devices in the United States. They're typically kept private for 6 months after the device first goes on sale.
"These documents reveal technical and design information that has not been publicly disclosed in marketing materials and is protected by Apple Inc. as confidential and proprietary," wrote an Apple manager in a July 18, 2017 letter requesting confidentiality.
But "external photos" can't be kept secret forever, and apparently, Apple decided to use the gold version of its phone when it submitted the iPhone X for certification. It's unclear why it never came out or if Apple is planning to eventually launch this color.
Here's what the gold iPhone X looks like: