The release candidate for macOS Tahoe 26.7 carried references to unannounced hardware across home devices, iPhones, iPads, AirPods and Macs, plus a video showing AirPods with cameras. Code for unreleased products shows up in early Apple betas fairly often. A release candidate is a different thing, as MacRumors set out: it is the final version of the software, handed to developers a few days early for testing, so it is not meant to include anything Apple has not already signed off.
In his Power On newsletter, Mark Gurman offered the likeliest explanation. Apple assembles a release by merging separate branches of work, and it keeps internal builds that carry software support for hardware it has not announced yet, so the code can be written and tested ahead of a launch. One of those internal builds, he believes, was merged into the branch destined for release, and “something that was supposed to remain inside Apple got tangled up with the shipping software – and made it all the way to the release candidate.” Expect the references to be stripped out of the public version. The camera AirPods are not expected until 2027, and the hardware in the video is believed to be a version Apple has already shelved in favor of a newer model.