Accessibility: It should also close when the user presses the Escape key.

[ACPK]

A tooltip typically becomes visible, after a short delay of generally one to five seconds, in response to a mouse hover, or after the owning element receives keyboard focus. Just as it is opened automatically, without user request, it is closed automatically when the focus is lost or on mouse out. It should also close when the user presses the Escape key.

https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Roles/tooltip_role