Added the trailing / after index.php to evade an internal server error on the Uberspace Apache installation were the lack of this broke the site, it internally replaced the URL-Path contents e.g. with index.phpadmin/ which won't work.
Also added a rule to make this folder our DocumentRoot, since this site is mostly run under domains/subdomains.
May be an issue related to my RedirectRule from HTTP to HTTPS placed in all DocumentRoots:
#RewriteCond %{HTTPS} !=on
#RewriteCond %{ENV:HTTPS} !=on
#RewriteRule .* https://%{SERVER_NAME}%{REQUEST_URI} [R=301,L]
