The "HomeAccessory17,1" identifier suggests that the new device is a previously unknown category of Apple devices, distinct from the HomePod's "AudioAccessory" identifier. It is speculated to run a variant of tvOS and be capable of running Apple Intelligence, powered by the upcoming A18 chip, also expected in the iPhone 16 lineup. This hints at the possibility of a new smart home hub with a built-in screen, similar to Google's Nest Hub.
The tvOS 18 update hints at a HomePod with a touchscreen display, as a unique touchscreen interface called "PlasterBoard" was found buried in the update5. This interface is relevant to the HomePod since its software is an offshoot of the tvOS software. Apple is rumored to be working on various home control devices, including a HomePod with a touch display, a hybrid HomePod and Apple TV device, and an iPad/HomePod combo as a centralized home hub.
The "PlasterBoard" interface found in tvOS 18 is believed to be a touchscreen interface intended for a future HomePod with a built-in screen. This interface, discovered by 9to5Mac, resembles a Lock Screen with a passcode keypad and is in line with Apple's naming conventions for other user interfaces3. Its presence adds to the evidence that Apple is working on a HomePod with a display.