Haha. Popos gnome doesn't have this. You get a pop up and says 60s count down. Wish I knew what command that is. I usually have hotkey 'poweroff' and that ista kills everything and shuts down lol
The command shutdown defaults to 60s, but doesn't throw the popup. shutdown +60 will give you 60min instead (and +30 is 30min, etc), shutdown -c to cancel, and shutdown --show will show if one is scheduled shutdown -h I believe is the "do it now" option but I always just give it the minute.