According to Apple's release notes for the update, watchOS 10.0.2 includes bug fixes and important security updates for the Apple Watch.
watchOS 10.0.2 can be downloaded for free through the Apple Watch app on an iPhone running iOS 17 by opening it up and going to General > Software Update. To install the new software, the Apple Watch needs to have at least 50 percent battery and it needs to be placed on a charger.
Today's update appears to be limited to the Apple Watch Series 9 and the Apple Watch Ultra 2.
