It's turns out that you can access the pixel 4 face detection IR camera via normal getUserMedia. The interesting thing is that if you try to do face unlock when this camera is being used (the bit where it throws things on to your face) the system will just flat refuse to do any of the face unlock process and that makes sense.
If you want to quickly try this then you can view the demo here.
Anyone got any ideas about what we can do with infrared camera access?
Update
Francois Beafort updated Blink by adding infrared to the camera name if the
device supports it - this will let you quickly get a better understanding of the type of camera just by the name (also will let users pick the one they want more effectively).