Last week, Microsoft accidentally released an internal build of Windows 10 for desktop. Build 16212 is from the internal branch rs_edge_case, and includes a few noteworthy changes over the last public preview build, 16199. As always, here's a quick video walk-through showcasing all the new things.
Build 16212 includes more behind the scenes than it does on the surface. It has several CShell components for desktop which are not active yet, unlike the Mobile build which we went hands on with here. The Desktop build is more or less the same as build 16199, with some additional settings.
Microsoft did not intend for this build to be released remember, and it has been pulled since. Microsoft will be rolling out a newer Insider Preview build this week if everything goes to plan, so stay tuned to Windows Central for a video walk-through of that build soon.