code: private void obtainButtonBarElevation() {
          int elevation;
  
          try {
              elevation = ThemeUtil.getDimensionPixelSize(this, R.attr.buttonBarElevation);
          } catch (NotFoundException e) {
              elevation = getResources().getDimensionPixelSize(R.dimen.button_bar_elevation);
          }
  
          setButtonBarElevation(pixelsToDp(this, elevation));
      }
docs: Obtains the elevation of the button bar, which is shown when using the activity as a wizard,
  from the activity's theme.