Where should the uwsgi_params file be located and what is its extension?

Question

I am having trouble wrapping my head around how this file works. I seem to see it in every example. See below:

server {
  listen 80;
  server_name sivusto3.fi;
  access_log /var/log/customersite3/access_log;
  location / {
    root /var/www/customersite3;
    uwsgi_pass 127.0.0.1:3033;
    include uwsgi_params;
  }
}

Answer 1

uwsgi_params file is located inside Nginx directory (/etc/nginx on my Linux machine)

me:~$ ls /etc/nginx | grep uwsgi
uwsgi_params

and has no extension.