Presence and connection only. FAIL solely on missing MANDATORY structure.
AXI4 internal is NOT_APPLICABLE, not FAIL. RECOMMENDED never FAIL. No L1–L3
and no invented ohms/mm/ps.
physical_bus_instance from declaration, silicon/part, pin/net names, and
pairs. USB and DDR fixtures emit groups; AXI4 internal attaches no PCB
nets. Ambiguity is REVIEW, not FAIL. No L0–L3 certifier and no invented Z.
michele