Look away, it pauses. Look back, it plays.

1. Paste a YouTube link above, or open a video file from the tablet.
2. Allow the camera when asked. It stays on this tablet. Nothing is recorded or sent.
3. Tap ⛶ for full screen. Prop the tablet so the front camera sees your face.

Netflix, HBO Max and LinkedIn Learning don't allow their videos to play inside another page, so they can't work here. On a computer, the Eyes On Chrome extension handles all of them.