Answering my own question:
https://developer.apple.com/videos/play/wwdc2025/208 starting at 8:45, but there’s no explanation, just the sort of “we’ve always been at war with eastasia” one expects from Apple’s polished statements.
One story I’d like to add. This is more in the category of mouse trails and shake to locate.
I installed the Master Control Program (yes, MCP) on my AmigaOS 3.1 in the mid 90s. This allowed me mouse actions I had not seen anywhere else before. The curser disappeared when I started typing or I could scroll in an unselected window just by moving the mouse curser over it.
2/2