It only works on Chrome-basedr browsers (Chrome, Opera, Vivaldi, Brave). AFAIK

IIRC, Edge Dev Tools is supposed to support more of it on Insider Builds. I'm not on an Insider build at work to verify, though.

Yes, thank you I love getting to the bottom of things. I tried disabling mine though and it still works. I think that's it for me though right now- could be a number of different things but I'm working on something else at the moment heh.

That's not what it is supposed to end up with. It's supposed to end up with a big Windows logo on a black background, with a message below that, and the link at the bottom.

Here is a screenshot showing what it looks like in Chrome on the left and Safari on the right: https://imgur.com/gpSMx44

Firefox 62.0b9 is similar to Safari, except the blocks are all black instead of colored, and the relative dimensions are different.