For anyone wondering, you can access this by tapping the button showing a 3D cube at the bottom left of the 3D viewer. The button may be cut off if you're viewing in a web view in another app like I was.

The AR viewer runs with a much higher frame rate and you can get closer to the model. However the lighting is significantly worse, which ruins the appeal. The in-browser viewer is choppy and I can feel my phone getting a little warm, but it looks a lot more like viewing the real artifacts.

Interesting, on desktop Firefox I can barely zoom in past the point that the object fills the FOV.

I want to be permitted to navigate up close to a point where I can see the pixels and triangle meshes, as if I was a millimeter away from some brush stroke or chisel mark, and then back out just a bit.