Every boundary of the facility has to be rigid and durable, suited to the environmental conditions it faces, and able to take the wear and tear that can be expected without containment being lost. Transparent sections must be glass, polycarbonate sheeting or a comparable durable material. All boundaries must either resist impact or be protected from it; the note explains this means standing up to things such as hailstones, debris carried by wind, birds, and objects moved by machinery.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.