docs: public List<String> listDefinedBuses() {
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) {
              SibTr.entry(tc, "listDefinedBuses", this);
          }
  
          List buses = null;
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) {
              SibTr.exit(tc, "listDefinedBuses", buses);
          }
  
          return buses;
      }