Exit the "Do you want to save your changes?" dialogue as fast as possible (discard changes)

When I press cmd-q or cmd-w on an app, sometimes I get a popup like:

I just want to quit the app as fast as possible, I want to select the "Revert Changes" or "Don't Save" etc. equivalents without having to move my hand to my mouse/trackpad, move the mouse cursor to the button on the screen, and click.

I don't want to have to take my hands off of the keyboard.

cmd-backspace used to work for me

But it doesn't anymore, at least not in Preview.app.

What's the new solution in Catalina?

Press the Spacebar.

⌘ + Backspace works if you are trying to choose “Don’t Save” but the Spacebar is what you want to select ‘Revert’.

You could use Keyboard Maestro to check which buttons exist and then press the appropriate one. For example, I've bound cmd+shift+w to check for "don't save" and a few other options. It will then use the press button action to press "don't save" or whatever

This will work as long as you add any new dialogues to your if/else statements. I have like 3 and it deals with 90% of cases.

If you need a super generalized solution, you could just hit the appropriate number of tabs and then hit space. The problem with this is that sometimes there are a lot of extra fields in between the start and the "don't save" button