Default port of the browser

Recently I have been learning nginx and learn about nginx configuration. I have been wondering how nginx determines which port the request is sent to the host when I enter the http://192.xx.xx.xx in the browser,

Port 80 is written in the nginx configuration file (as shown below). However, the problem is that I did not write it in the address bar of the browser. Later, I checked the relevant information online to understand the reason.

#
# The default server
#
Server {
Listen 80 default_server;
Server_name _;

# Charset KOI8-R;

# Access_log logs/host. access. log main;

Location /{
Root/usr/share/nginx/html/KB /;
Index index.html index.htm;
}

.....................

Reference:

Q: In the browser address bar, enter \ 192.168.1.1, which Port will access the host by default?
Answer:
① If it is \ IP, the browser will implicitly convert it to file: // IP, which is ports 135 and 445
② If it is an IP address, the default value is HTTP. This is port 80.

Default port of the browser