Microsoft pulled a quick one on its pool of Windows Insiders and released build 10049 of the Windows 10 Technical Preview less than two weeks after the last build was made available to Insiders who were signed up for the Fast Ring update sequence.
The Redmond company said they would begin using the Fast Ring for pushing builds out much faster and this appears to be a very good pace they are looking at. I know it may not stay this fast but it is nice to get a new build so quickly following the last one.
Another reason this build is significant for testers is it contains the first official public preview of Project Spartan, Microsoft's new web browser, which has been very highly anticpated.
You can read more about the build here at the Supersite and learn about some of the fixes and known issues in this latest build of Windows 10.