Can you use Eleventy to generate PHP files instead of HTML?

[jcubic]

I'm just wondering if you can have a simple website with PHP files that can have some augmentation to the generated HTML.

Can you change the extension of the output files? I would be able to put some additional PHP code into the templates. I would like to keep the directory-based permalinks. So the index.html becomes index.php.

Or is something like this completely nonsense?

[Ryuno-Ki]

I'd try fiddling with permalinks here. That could still happen on directory-level.