You can log the user out by changing the “realm” parameter, which is a freeform string and can be quite long. As well, setting realm will cause devtools to use cached credentials similar to a new tab.

“No themed login form” oh no! Anyway. (I really think that the “theming” on login and sign-up forms breaches which bits are done by the browser and which bits are not. We’ve had to kludge back support)