Configuration method of nginx https reverse proxy http

In some scenarios, https is used to reverse proxy http through nginx. The configuration is as follows:

upstream mobileapi {
    server           10.1.10.13:80  weight=1 max_fails=1 fail_timeout=60s;
}

server {
       server_name                    mobileapi.xx.com;
       listen 443 ssl;
       ssl on;

        ssl_certificate        /home/wwwroot/ssl.xx.com/xx.crt;
        ssl_certificate_key    /home/wwwroot/ssl.xx.com/xx.com.key;

        ssl_session_timeout  5m;
        ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
        ssl_ciphers AESGCM:ALL:!DH:!EXPORT:!RC4:+HIGH:!MEDIUM:!LOW:!aNULL:!eNULL;
        ssl_prefer_server_ciphers   on;            
 
    location / {
        proxy_next_upstream http_500 http_502 http_503 http_504 timeout error invalid_header;
        proxy_pass                http://mobileapi;
        proxy_redirect            http://mobileapi https://mobileapi;
    
        proxy_set_header        Host            $host;   # ???  $http_host;
        proxy_set_header        X-Real-IP       $remote_addr;
        proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header        X-Forwarded-Proto $scheme;
        add_header              Front-End-Https   on;

     
        }
}