It’s the info you get from using the mouse to hover over things on the screen.
That patch note is saying they disabled cursor mode in Alt only. They did not disable it in tab. All of the items that appeared on Alt also appear on tab where the cursor is still enabled and you can see extra info by hovering over an object on the screen.
An article written for people who do not exist. People who will listen to this article who are in the overlap with people who need to hear it.