Install the Windows SDK from [https://developer.microsoft.com/en-US/windows/downloads/windows-10-sdk here].
Install Download the DebugView, a tool published as part of Microsoft SysInternals, from [https://technet.microsoft.com/en-us/sysinternals/debugview.aspx here]. Extract DebugView.exe (and dbgview.chm if you want the help file) to a location where you can run it from (desktop, for example.)
== Toggle the Direct3D Debug Layer Pref in Firefox ==