[rclkrtrzckr]

Isn't ".pl" actually used for perl?

Well, there might be a Prolog interpreter written in (a) perl (regex) ...

[ajdude]

Prolog was using .pl for a bit over a decade before Perl existed.

[userbinator]

My first thought upon reading your comment was "it's used for Poland" ;-)

[thijsvandien]

Then using .prl in stead wouldn’t have helped much…

[tikhonj]

It's used for both which consistently confuses logic that guess programming language purely based on file extensions.

[jimjimjim]

Prolog is a older than Perl and there doesn't need to be any exclusive claim on file extensions.