We were having a problem with a redirection issue in one of our projects. We had a page that had the url(i.e. path alias in Drupal) as /index. Whenever that page was called, Apache would append to it .php extension and the request gets routed to index.php which is NOT the desired effect.

This was due to the option "MultiViews" being enabled on our new Debian installation. For more info, read this.

I added this line to our .htaccess.

# MultiViews is evil. It automatically adds .php to /index. 
Options -MultiViews

This should be added to all our .htaccess in general in case we go to deploy to a host that has the option enabled.