code: protected function asIntegerStringFallback($value)
      {
          if (empty($value)) {
              $value = 0;
          }
  
          $value = $this->normalizeNumericStringValue((string) $value);
          $separatorPosition = strrpos($value, '.');
  
          if ($separatorPosition !== false) {
              $integerPart = substr($value, 0, $separatorPosition);
          } else {
              $integerPart = $value;
          }
  
          return $this->asDecimalStringFallback($integerPart, 0);
      }
docs: Fallback for formatting value as an integer number by removing any decimal digits without rounding.
  
  @param string|int|float $value the value to be formatted.
  @return string the formatted result.
  @since 2.0.16