The index.html file in the XAMPP htdocs folder has a redirect
script to a php file that is never going to open by clicking onto it in its
htdocs location, or at least I never could get it to open that way (it, of course, can open under the localhost through the browser). But,
when you substitute your own index.html file for that one and change
your local server to your www.whatever.com
in the html.conf, the index.html is recognized immediately by Apache2 & works just fine as your home page while serving it on the web.