Where planned large scale dealings will use single-use components (for example single-use bioreactor bags, tubing and filters), those components must be able to be leak tested before GMOs are loaded into them. The guideline suggests filling single-use systems with media before inoculation so leaks can be found, which lets bags and any attached open lines be tested at operating pressure, and looking over the remaining tubing, lines, fittings and filters by eye before GMOs go in.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.