As expected, this newly leaked build of Windows 10 features a ton of improvements over what we've seen officially in the Windows 10 Technical Preview. And it makes me wish we could go back to the old days of weekly builds during Windows betas.
Anyway, there is a lot here. But based on just a few minutes of tooling around in the build, I can make some corrections and additions to my previous article, Windows 10 Build 9901 Leaks with Numerous Changes.
Wallpapers. There are five new wallpapers in all in this build, the new default wallpaper and four in the set Lines and Colors (replacing the ones from previous builds and from Windows 8.x). The wallpaper set Flowers remains unchanged in this build.
Cortana. Cortana is integrated as part of a new Search experience. So where we got a Search taskbar button in previous builds, this time we have a choice of a Search button or box on the taskbar, or you can disable it as before. Search works against both your local PC and the web.
Charms. While the Charms do work as before, the Settings charm has been removed. That's accessed through the app settings menus now. And WINKEY + I brings up the Settings app, not the Settings pane, as before.
Taskbar buttons. In addition to its new opaque black* style, the taskbar places a line under buttons that represent open Windows, and the current window appears selected. (In previous versions, you'd see a selection box around all of these buttons.) It's a lot more subtle. Changing the color in Personalize doesn't impact the taskbar (for now?), just windows and the Start menu/screen.
(*Update: The taskbar isn't actually black. It's a very dark version of the foreground color you choose in the Personalize control panel. --Paul)
Full-screen button on Modern apps. There is a prominent new full-screen button in the title bar of Modern app windows. And as noted, that "hamburger" menu has replaced the old window menu button.
Settings pane animation. As noted previously, app Settings panes ("fly-outs") now appear within the frame of the window. But they also visually "fly-out" from the edge of the screen, which is a completely pointless animation no matter how much you like this kind of thing.
Store and Store Beta. Many of the new apps I pointed out in the previous articles sit in this build alongside the old versions. So you can access both Store and Store Beta, for example. Store Beta isn't all that graphically filled out yet, except for the Music experience.
Xbox app is nothing special. After speculating about the Xbox app, I can now see that this is just a replacement (overdue at that) for Xbox Games. Xbox SmartGlass remains.
Photos. There are two apps in this build, both named Photos. But the new one does appear to be a nice improvement over the terrible version from Windows 8.1.
Settings. There's a new Settings app as noted, but if you dive into any of the options you'll see a familiar interface (like that from Windows 8.x) but with some new options too.
I'll keep digging...