You can access your site in two ways: http://example.com or http://example.com/index.html(or .php). Only one way should be used. Both ways is incorrect.
Ex. https://demo.youphptube.com/index.php
https://demo.youphptube.com
index.html its not in the files of the site
yeah? theres nothing wrong with that, thats how it is supposed to be.
the current behavior is perfectly normal.
its ok