The Windows 10147 has been given by WinAero:
http://winaero.com/blog/windows-10-build-10147-is-leaked-download-iso-image/
They list a .iso and a generic product key here NJ4MX-VQQ7Q-FP3DB-VDGHX-7XM87
During installation you are prompted for a product key:
Note I state a generic product key as it allows for installation but not product activation in the same manner as Windows 8.1 generic product keys:
If I select Store…
As this is a leak likely it doesn't work. In combination with the data provided here:
It seems like Windows Insiders will be offered Windows 10 product keys possibly through an updated Microsoft Store and when Windows 10 RTM comes out, Windows 7 and Windows 8.1 users will be offered product keys via the Get Windows 10 App.
Note I also tested the ability to move documents, pictures, music and videos to another drive it seems to not work correctly:
