On top of 8.1, the supplier puts forward and records ways the owner could set targets better; when asked, helps the owner build baselines by supplying environmental impact information about the product or material; puts forward and records ways to improve the owner's baselines; and, whenever it says a product or material carries less carbon than another, frames that comparison on the baseline assumptions the owner has specified.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.