If you're be looking for information about Windows Update processing in Windows 10, you should know about a change that is introduced with Build 9926. In the past, the WindowsUpdate.log file (location: %windir%\Windowsupdate.log) provided information about updates downloaded and installed, and whether update installations were successful or not, among other things.
If you open the WindowsUpdate.log file in Windows 10 Build 9926, you'll be met with a placeholder message:
The "go" link (http://go.microsoft.com/fwlink/?LinkId=518345) in the WindowsUpdate.log file message points to a non-existent KB Article (though it currently lands on the Windows Insider front page), but that article should go live eventually to describe the how to troubleshoot Windows Update issues in Windows 10.
In the interim, you can get a good understanding of Event Tracing for Windows, in a Microsoft blog post from 2009, entitled: ETW (Event Tracing For Windows) – what it is and useful tools.
Obviously, what will be introduced in Windows 10 will be a much improved version of ETW than what was presented in 2009.
Thanks to Susan Bradley (MVP, and Patching maven) for the heads-up.