[therein]

I imagine they get it from some Amazon API, however I don't have the specifics.

Take a look at the information it displays: https://i.imgur.com/ZbgfSlo.png

Ignore the price bit, it normally shows the price right but there must be a minor transient issue right now.

But as you can see, Amazon claims the product is sold by Sony. However most of the sellers are not Sony.

As you said, having a customer-oriented variant of this functionality would be an amazing feature for a browser extension.