We have that on the most recent generation of Framework Laptop. When the hardware privacy switch is engaged, the image sensor is electrically powered off and the camera controller feeds a dummy frame with an illustration of the switch.
Happy Framework customer here, I just wanted to say thank you for all your efforts on privacy.
Is there a video or some images of this somewhere? I would love to see a demonstration.
I looked it up on YouTube
https://www.youtube.com/watch?v=k6AsIqAmpeQ&t=1145s
And adding 2+2, the man being interviewed (Nirav Patel) is the same man who replied to my comment (HN user nrp), i.e. the man who actually did the overengineering.
If you rewind to 17:03, he talks about the changes of what the switch does (previously: USB disconnection, now: as he described in grandparent comment).