BUILD 2015 begins tomorrow, and I expect we'll learn the last features that Microsoft intends to add to Windows 10 at launch. The conference is targeted at software and web developers first and foremost. We might not see too much on the consumer side, but we should get under-the-hood information that will be relevant to consumers. For instances, some questions about Windows Store, WinRT, and DirectX 12 might be answered. We might even get a public DirectX 12 SDK (and more).
Note: WinRT (API) is not the same as Windows RT (OS).
As we noted earlier, development was forked into a 100xx-branch and a 101xx-branch of build numbers. We assume that, due to the proximity to the conference, the lower build number is getting polished for public presentation while the higher builds will surface later, with more experimental features.
Microsoft published an introduction video, based on the 10061 build, to introduce the new OS to new users. I guess they are expecting a new wave of testers after the conference, probably both developers and enterprise evaluators. It is brief but interesting, although it surprisingly did not mention anything about the “Continuum” interface to switch between mouse/keyboard and touch experiences.
As stated, BUILD 2015 starts tomorrow and we will probably have a bit of coverage for it.