Changing extension from .php

There used to be a variable defined in the index.php of CI that stored the extention to be used.

In CI 2.x it was already deprecated:

Code:

// The PHP file extension
// this global constant is deprecated.
define('EXT', '.php');

And it has been removed completely in 3.0. I've checked a few core files and they all have hardcoded '.php' references. Not quite shure why CI made the switch from dynamic to a static situation.

But I neither can imagine why one would want or need to change the file extention of a .php file. The only reason I can think of is using file extentions to force using another php version handler, like using php 6 for .php6 files, php5 for .php5 files etc.
If needed you could change the php handlers for a specific directory/vhost in the apache config itself. This way you can use whatever handler you want without changing any files.