My code is extremely simple:

const response = confirm("Message");
console.log('done');

Edit: it turns out it has nothing to do with dev tools - it's whether my focus is on that tab or on a different one.

If I have the dev tools closed, the confirm modal simply does not appear and it skips straight to printing done. I have the dev tools open, the confirm modal appears.

I am kinda lost on this one, am I missing something here? If I just write setTimeout(() => { confirm() }, 3000) in the dev tools of a random tab and then close the dev tools, then the confirm still appears there. But with the actual code running on my page...nothing.

Edit - it may be that it only appears if my focus is on the page in question? Is there a rule around that?