It's been many years since Google was first reported to be working on Fuchsia, a new operating system that was believed to eventually replace Android and Chrome OS with a unified platform. In the time since 2016, when the discovery was originally made, many reports have come out about the OS, including the ability to install some version of it on the Pixelbook in early 2018.
It's never been officially announced as a platform for any of its devices, though. At least, not until now. According to 9to5Google, the Mountain View giant has confirmed that it's rolling out an update to Fuchsia OS to users of the original Nest Hub. The update will replace the Linux-based "Cast OS", as it's referred to, with Fuchsia, but you shouldn't expect to see any big changes - or any visible changes at all. As noted in the report, Google's software experience for smart displays is built with Flutter, which is meant to offer consistent experiences across platforms, meaning everything should look and feel the same.
Despite that, Google appears to be taking a cautious approach due to the big under-the-hood changes that come with the update. It will be rolled out over the next few months, starting with users in the preview program. There's no indication right now that Fuchsia is coming to other devices anytime soon, but the goal of this rollout should be precisely to test the viability of the platform before pushing it to more people.
Google held its developer-focused event, Google I/O, last week and Fuchsia was never mentioned during its keynote, so whatever changes are being made right now aren't likely to make a huge difference for users in the near future. It'll be interesting to see where the operating system goes in the next few years, seeing as it's apparently capable of running Android apps natively and it could run on phones and PCs.
In the meantime, Google recently announced Android 12 and a new version of Wear OS, both of which are major upgrades to their respective platforms, so we already have something to look forward to. It remains to be seen if Fuchsia OS will ever become the platform for all of Google's devices.