The leaked Windows 10 Pro Build 10151 of GVLK has the build string of 10151.0.150617-1826, and is from fbl_impressive, the branch which almost all leaks came from.
Windows 10 Pro Build 10151 File Information
File Name: 10151.0.150617-1826.FBL_IMPRESSIVE_CLIENTPRO_VOL_X64FRE_ZH-CN.ISO
MD5: C45F6E1C6066C655FA2665AA30FB5BE0
SHA1: E3434110457A8D28FB5EC54DA18C261AD938F692
CRC32: EAA239C4
Unfortunately, no en_US English language pack is available to convert the ISO to English yet, although some hack has started to appear in the form of homebrew ISO which integrated English language pack from Windows 10 Build 10154 and registry trick. And WZOR, the famous Russian leaker, apparently has Windows 10 Build 10154, but does not yet leak it.
Update: Windows 10 Build 10158 (official release)
Changes in Windows 10 Build 10151
Start
- More apps now use the accent color as their tile color
- The full screen start menu now shows the power and all apps button at the bottom
- The hamburger button no longer shows a notification icon when new apps are installed, this is now shown at the all apps button
- New animations for tiles, including the added-then-removed-now-added-again 3D-animation
- New boot animations for apps
- Most WinRT tiles can now take the large tile size (including Edge, Calculator, etc)
- The smilies for additional icons above power have been replaced with actual indicating icons (and some have been updated)
- Full screen start is now aligned higher, allowing more tiles in the height without a scrollbar appearing
Interface
- The window chrome of Win32 apps is now the same as for WinRT apps
- The clock, language and other notification-fly-outs have been updated with a transparent background
- The back-button no longer takes the accent color in some apps
- Apps no longer have to take a white icon on the taskbar anymore
- More apps have a tile-less icon on the taskbar
- Multiple icons have been revamped
- All Win32 controls have been given a redesign
- The installation experience has been updated, it also introduces more apps
- There are new default wallpapers
- Properties windows have received a visual update
- In tablet mode, icons no longer disappear behind the Task View, Search and Back button when app icons are shown
Features
- Action center
- New quick settings for Notes and Quiet hours
- You can now set a timer in the snapping tool
Edge
- Project Spartan has been updated from version 15 to 19 and is now called Microsoft Edge
- Edge has new icons
- The feedback icon has been removed from the main bar
- There is a new share icon on the url bar
- You can now enable a dark theme for Edge
- Improved ECMAScript 6 support (without flags)
- You can now manage your passwords
- You can now change the search provider
- When closing Edge with 2 or more tabs open, it will now warn you
- Pinned hubs now look better
- You can now show a home button
- Pinning sites to start is broken in that it no longer has the site’s theme, but a normal Edge logo
Apps
- Multiple apps have been updated
- The “Store” apps has been removed, leaving only “Store (beta)”
- New “Get Office” app
- New “Phone companion” app
- Settings
- There are new animations when switching applets
- Automatic color picker now works
- You can now enable features that aren’t enabled by default through Windows Update
- You can now exit the Windows Insider program
The final RTM of Windows 10 GA is on July 29th, 2015.