Ubuntu tried to use a macOS style menu bar back in the Mir days, but in my experience that didn't quite work. I ended up with some applications using the global

Ubuntu tried to use a macOS style menu bar back in the Mir days, but in my experience that didn't quite work. I ended up with some applications using the global menu bar and others using their own, adding two menu bars right next to each other when the window was maximized. For a macOS design feature like that to work, you need every application to use the specific APIs to integrate with it, or it'll just add to the GUI mess. Ubuntu had the power to override APIs as they wished, a theme like this probably shouldn't do that, so I don't think there will ever be a stable theme that'll add a macOS menu bar.