I have now had this problem about every year for the last three or four years, and every time have completely forgotten how I resolved it the previous time. It’s especially annoying, because usually involves searching for such common terms as
directory, etc. which result in almost entirely useless information.
So, here, for my own future reference, is how to stop a stupid Apache from serving
/index.php (at, of course, any depth of the path):
So easy. The documentation explains it all.
I’ve just added it to the WebDB .htaccess.