What is AppZero’s runtime intercept layer?

AppZero adds a layer – the intercept layer -- which gives a different view of the machine to include the contents of the VAA.  From the application’s point of view, it looks as if it’s been natively installed on the hard disk.  The reality is that those files are still in the VAA.  But the application’s view is a merged view of what is in the VAA and the OS.