Apple's habit of late has been to release most of its operating system updates for each platform all on the same day. But in one recent instance, though, macOS and watchOS came a single day after iOS, iPadOS, and tvOS updates.
The macOS update mainly adds features we already saw yesterday in iOS and iPadOS 13.2. That includes support for AirPods Pro, the ability to opt in or out of sharing Siri recordings with Apple, new emoji, and new HomeKit feature support. There are also a number of macOS-specific bug fixes and the restoration of some lost Photos features.
Here are Apple's update notes for macOS Catalina 10.15.1: