What AR/Lidar app is this?
Solution 1:
It is the app called "Canvas: Pocket 3D Room Scanner" by Occipital!
Find it on the App Store here:
https://apps.apple.com/us/app/id1514382369
You can watch their marketing video about the app here:
https://www.youtube.com/watch?v=l_kG_kSYFUU
Note that the functionality in the video is only available on the iPhone 12 Pro and the 2020 iPad Pro (the models that have a LIDAR sensor).
And here's their web site clearly referencing that the app was featured in the mentioned Apple Event:
https://occipital.com
"(Featured in Apple Event October 13, 2020)"