Engine... thanks for this. Product coding, in my limited experience, has been one of the messiest and most confusing areas in ecommerce.
It's good to see Google attempting to provide some clarity, not only in product classifications, but also in distinctions for their use among, eg, manufacturers and resellers.
In the broader picture, Google appears to be tackling the chaos of identification... a lack of standardization which has been one of the major sticking points... not only in ecommerce, but... IMO... in the sharing of data (and data-based "tangibles") of all kinds.
I'm seeing this as a partial extension of the work pushed forward by John Giannandrea, the founder of Freebase, who came in to replace Google's Amit Singhal in 2016.
The Head Of Google Search, Amit Singhal Is Leaving The Company Feb 2016 https://www.webmasterworld.com/google/4789368.htm [webmasterworld.com]
In that thread I posted about what I thought Giannandrea would bring to the company in the way of enhancing the knowledge graph. I have no inner pipeline to know exactly what he did at Google, but that does seem to be the direction he was going.
In the video I linked to, he notably said:
"We are awash in un-reconciled data"... and I relate that comment to this emphasize on product information now.
Unfortunately, the linked video had major audio problems... but, with Google's automatic captioning, it is now much easier to follow and is well worth viewing. (I believe somewhere I've seen the same presentation with remastered audio, but can't find it now.)
As engine suggests, the product document is an essential reference.