The com.apple.MobileAsset.UARP.A2538
MobileAsset type contains firmware updates for Apple Pencil Pro.
It's published in mesu for iOS (manifest) and macOS (manifest).
The manifest was first published on 13 May 2024 , when the first firmware update was released.
For the release history of Apple Pencil Pro firmware updates, see the OTA Updates/Apple Pencil Pro page.