code: @Nullable
      private Integer processArrayElementStore() {
          if (stack.getStackDepth() >= 2) {
              OpcodeStack.Item itm = stack.getStackItem(2);
              int reg = itm.getRegisterNumber();
              if (reg != -1) {
                  WrapperInfo wi = wrappers.get(Integer.valueOf(reg));
                  if (wi != null) {
                      OpcodeStack.Item elItm = stack.getStackItem(0);
                      wi.wrappedReg = elItm.getRegisterNumber();
                  }
              } else {
                  OpcodeStack.Item elItm = stack.getStackItem(0);
                  reg = elItm.getRegisterNumber();
                  if (reg != -1) {
                      return Integer.valueOf(reg);
                  }
              }
          }
  
          return null;
      }
docs: processes a store to an array element to see if this array is being used as a wrapper array, and if so records the register that is stored within it.
  
  @return the user value representing the stored register value