Where online verification equipment such as bar code scanners checks labels and printing, procedures for running and testing it must make sure it is correctly set up and can raise an alert or reject packaging that is out of specification. It is tested when each run begins and when it ends, and at a frequency that reflects how much implicated product the site can hold back, and there are procedures for when it fails.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.