code: private void obtainRestoreDefaultsButtonText() {
          CharSequence text;
  
          try {
              text = ThemeUtil.getText(getActivity(), R.attr.restoreDefaultsButtonText);
          } catch (NotFoundException e) {
              text = getText(R.string.restore_defaults_button_text);
          }
  
          setRestoreDefaultsButtonText(text);
      }
docs: Obtains the text of the button, which allows to restore the preferences' default values, from
  the activity's current theme.