Is there anything like KDE's CTRL+META+ESC (xkill) for GNOME?

When you hit CTRL+META+ESC on KDE, you get a skull icon and you can kill any windows you click on.

It’s basically xkill, but for Wayland, built right into the compositor.

Does GNOME have the same thing mapped to a keyboard shortcut?

No.

Mutter has code to terminate a client (either X11 or wayland), but it is only used by the “app doesn’t respond” dialog; it is not exposed directly to users.

Every window in the overview has an X in the top right corner, which closes the app. I’ve never had it fail with apps that aren’t responding.

Ditto! The X thing only works with the mouse. I tried selecting an app with the keyboard and pressing Delete, but it did nothing.

In this case, I was stuck in a mode where transformers_ocr was trying to take a screenshot, but wasn’t responding to any input besides my cursor moving. My entire desktop wasn’t frozen, but I couldn’t cancel the screenshot or take a screenshot for about half a minute.

I think the only way to kill it if this behavior persisted would have been to switch to a tty and run pkill -9 transformers_ocr.