The ID is driver assigned and is implementation dependent. It's much like compiler warning numbers. You can chose to ignore specific items by ID, sort errors by their IDs and so on, but there is no cross-vendor meaning to the number.
thanks for your reply, I knew that ( from your book :-) ) already and that is also the reason why I asked here in AMD forum. My GL Context is running on an AMD Kaveri 7800 and I thought those IDs do mean something vendor ( AMD ) specific. So they don't give deeper insights into the error source, other than being sortable and switchable.