Hi Andrew.
I’m happy that you liked the article and thank you for the great question.
At first I too thought Google was able to hide the url to their models (taking that Panda model as an example) but after poking around the code in the mobile inspector, I was able to find the url to the Panda model in the same way you can find the source of images in the “traditional” desktop inspector.
If you prefixview-source:
to the google search url on mobile and then use the “Find in page” feature of the Chrome app to locate the HTML for opening the 3d model (looking for the text “Meet a life-sized” should take you there), around that part of the code you will be able to find the url to the panda model (https://storage.googleapis.com/ar-answers-in-search-models/static/GiantPanda/model.glb). As you can see in the screenshot below, by accessing that link I was able to download the model directly and and I even plugged it in a basic demo. I have used the model simply for the sake of this demo so first look into the copyright behind using these models if you intend to use them.
Granted, I know I have not given you a solution to hide the source of the models, but I hope this information of inspecting the code on mobile to find the Google models helps in some way. I’d say because the model-viewer component is so similar to the HTML img element, it seems like the issue of privacy for the source of the files remains similar too.
Once again, thank you for the question, it is quite pertinent to this subject.