[RobbieGM]

Pages can only close windows they opened, so this is probably a browser bug. It seems unlikely anyway that Google would try to get you to switch browsers through strange intentional glitches rather than clear messages.

[AdriaanvRossum]

You are right [1]. Didn’t know that is the case.

[1] https://javascript.plainenglish.io/closing-a-window-with-jav...