I think this is a web plug-in. The exam is conducted on the canvas, and the webpage mode starts with the login of the school account, and then the photo of the student ID card is taken. Live+means that the camera microphone is on and the teacher is watching you all the time, just like the building security guards are watching countless small monitoring screens. Review+ is an unsupervised pure video mode. The camera and microphone are turned on mainly to let AI analyze your face, sight and movements. If there is any suspicious behavior during the exam, your name will be marked, and then an expert will watch the video to analyze whether you cheated.
Once the exam begins, the video will be synchronized. People can't leave their seats, and their eyes can't obviously leave the screen.