Possible eBay API Exploit?

So I sell on eBay, I use a third party tool to manage my listings.

Just recently discovered that it seems the tool is able to get information that is usually hidden about other sellers. For example I can see a sellers SKU, or Quantity remaining (exact amounts when the sellers publicly displays 10+) of an item plus other small details. I wonder if this is something people are aware of, or if it's relatively unknown.

It has some fringe use cases, for example if you are selling a competitive niche you can get an idea into your competitors stock - also some people reuse their wholesalers SKUs so you can find their products source in some limited cases.

So has anyone been able to do this before, or is this new?

I don't see much of an avantage over anyone with this number really, unless you were a monopoly. I doubt its a bug, its probably just part of the info that the API provides. Have your reverse engineered your question and actually tried looking up how to find other sellers' info in the API docs? You could pay a visit to a big ebay facebook group and discreetly say you want to find out the details from other sellers via the API, is it possible?