Here’s a great tip from Dustin Freeman – sometimes you want to be able to record what the VR user sees in the headset, including all the Guardian system or Oculus Home stuff, rather that the sanitised second monitor view that you see on the PC normally. Luckily Oculus has a tool for that called The Compositor Mirror which ‘displays the content that appears within the Rift headset on your computer monitor. It has several display options that are useful for development, troubleshooting, and presentations.
Anything that appears in the Rift headset can be shown in the Compositor Mirror tool, including Oculus Home, Guardian System boundaries, in-game notifications, and transition fades. It is compatible with all games and experiences regardless whether they are developed using the native PC SDK or a game engine.’
you can find it here: C:\Program Files\Oculus\Support\oculus-diagnostics\OculusMirror.exe
more info here including the various display options