The box that pops up and counts down from 60 seconds whenever you attempt to log out, shut down or reboot is viewed by some (usually on laptops with their power button in an inconvenient spot on their keyboard, such as right next to the Delete key {hrmmmphhh... HP... hrmmmphhh}) as a god-send, and by others (usually with desktop computers) as a nuisance.
You can disable or enable them.
If you don't use flatpak: sudo apt install dconf-editor
If you do use flatpak:
flatpak install flathub ca.desrt.dconf-editor
flatpak run ca.desrt.dconf-editor
...wait for dconf-editor to start, then within the application, navigate to: /org/gnome/gnome-session/
and disable / enable "logout-prompt".
Just a note .... when using dconf-editor be VERY careful as one wrong move and you can really mess up your OS ..... in fact there is a warning that you have to except each time you open dconf-editor it tells you to be-careful and you have to hit the except button ....
Dconf-editor is a very powerful program just take a look around it a bit but don't touch anything until you are sure of what you are doing or you get instructions like Mr_Magoo gave above .....
