what is 1′”5000 IP address

I use some capture request for check any attack on my web application or not , today I found this (1′”5000) in my Columns That Store Src IP Send the Request , And Here What it send :

{
    "destinationIP": "MY.IP.IS.HERE",
    "destinationPort": 80,
    "headers": {
        "referer": "1'"3000",
        "accept-language": "1'"6000",
        "client-ip": "1'"4000",
        "host": "mydomain.com",
        "connection": "Keep-alive",
        "x-forwarded-for": "1'"5000",
        "accept-encoding": "gzip,deflate,br",
        "user-agent": "1'"2000",
        "via": "1'"7000",
        "accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"
    },
    "sourcePort": 60486,
    "sourceIP": "103.161.35.121",
    "requestURI": "/fonts/danapro/index/1'"1000",
    "httpMethod": "GET",
    "queryString": "N/A",
    "parameters": {}
}

it’s The Code for get SRC IP :

    private String getClientIpAddress(HttpServletRequest request) {
        for (String header : TextUtils.HEADERS_TO_TRY) {
            String ip = request.getHeader(header);
            if (ip != null && !ip.isEmpty() && !"unknown".equalsIgnoreCase(ip)) {
                return ip;
            }
        }

        return request.getRemoteAddr();
    }

And HEADER_TO_TRY :

    public static final String[] HEADERS_TO_TRY = {
            "X-Forwarded-For",
            "Proxy-Client-IP",
            "WL-Proxy-Client-IP",
            "HTTP_X_FORWARDED_FOR",
            "HTTP_X_FORWARDED",
            "HTTP_X_CLUSTER_CLIENT_IP",
            "HTTP_CLIENT_IP",
            "HTTP_FORWARDED_FOR",
            "HTTP_FORWARDED",
            "HTTP_VIA",
            "REMOTE_ADDR"
    };

And Question is how can getClientIpAddress return 1′”5000 to me? and what it is?