This leaked build arrives just two versions ahead of the latest public release from last week. As such, not much has changed, but some things have. First, Mail and Calendar have been replaced with an upgrade under the Outlook branding. Those apps make up the majority of known changes for this not-release. One change to Project Spartan has also been spotted by WinBeta in their walkthrough. Spartan now includes an “Open with Internet Explorer” option. The concept seems to be if you visit a website that was designed for Internet Explorer, you can easily switch to the other Microsoft browser.
A new app, Microsoft Family, has also been added but it currently consists of a Windows Live logo leading into a completely blank screen. More specifically, it is the Windows Live 3d characters in the same arrangement as the silhouettes on Microsoft Family Safety. As such, it will probably be a parental control application.
There will probably be a few more builds until we get one pushed down Windows Update, but at least we can see a bit more of what's going on behind the scenes.