Apple has released a pair of software updates affecting tvOS and the HomePod range, bringing them up to version 16.3.1.
The updates will install automatically onto each device in time, however you can manually do so on the Apple TV within the Settings app. The HomePod software update can be managed via the Home app.
It is unclear exactly what the content of the updates are, except for Apple's patch notes stating they include "general performance and stability improvements." The minute version number change to 16.3.1 also points to it being a minor refresh.
The last HomePod software update to version 16.3 included features enabling built-in temperature and humidity sensors in the HomePod mini and HomePod, with readings for each able to be seen within the Home app and by asking Siri for them.
Changes to ambient sounds, audio tuning for spoken content, and Find My alterations were also in the 16.3 update.