Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Calculation/TextData.php
public static function CHARACTER($character)
    {
        $character = Functions::flattenSingleValue($character);

        if ((!is_numeric($character)) || ($character < 0)) {
            return Functions::VALUE();
        }

        if (function_exists('iconv')) {
            return iconv('UCS-4LE', 'UTF-8', pack('V', $character));
        }

        return mb_convert_encoding('&#' . (int) $character . ';', 'UTF-8', 'HTML-ENTITIES');
    }
public static function CHARACTER($character)
    {
        $character = Functions::flattenSingleValue($character);

        if ((!is_numeric($character)) || ($character < 0)) {
            return Functions::VALUE();
        }

        if (function_exists('iconv')) {
            return iconv('UCS-4LE', 'UTF-8', pack('V', $character));
        }

        return mb_convert_encoding('&#' . (int) $character . ';', 'UTF-8', 'HTML-ENTITIES');
    }
public static function CHARACTER ( $ character ) { $ character = Functions :: flattenSingleValue ( $ character ) ; if ( ( ! is_numeric ( $ character ) ) || ( $ character < 0 ) ) { return Functions :: VALUE ( ) ; } if ( function_exists ( 'iconv' ) ) { return iconv ( 'UCS-4LE' , 'UTF-8' , pack ( 'V' , $ character ) ) ; } return mb_convert_encoding ( '&#' . ( int ) $ character . ';' , 'UTF-8' , 'HTML-ENTITIES' ) ; }
CHARACTER.

@param string $character Value

@return string
CHARACTER .