When running automated tests on the MediaWiki site, after a successful account creation or user login. When a user tries to logout, it once in a while displays a prompt asking the user to confirm if they want to log out or not.
This behaviour is irregular as it only happens a few times and not all the time, this can cause a test to fail when it happens.
I'm trying to get a screenshot of the prompt, but as it doesn't occur always, it's hard to know when next the prompt would appear so I could screenshot it.
The prompt button has a class .oo-ui-buttonElement-button ...