What is local after localhost.local in the hosts file?

We are developing by accessing http://fogefoge.localhost.local:3200/~ when we launch a local server in Rails, but if we delete the .local part in url, we get an error.

By defining it in the hosts file as follows, you can see that it is associated with an IP address, but I don't understand why .local should be added at the end.

 (/etc/hosts)
127.0.0.1 fogefoge.localhost.local

If you exclude .local, edit the hosts file, and then start up the server, and access http://fogefoge.localhost:3200/~, you will also get a Routing Error.

 (/etc/hosts)
127.0.0.1 fogefoge.localhost

If anyone knows anything, I would appreciate it if you could let me know.
Thank you for your cooperation.