I found perldoc.pl with a high usability level being up-to-date to version 5.30.0.
Perl.org links to perldoc.perl.org which stops at version 5.26.1. But on the other hand, it links to Download (version 5.28.2) to Strawberry Perl (actually version 5.30.0) which I find very confusing.
I already know that Perl 6 is a completely different language. Is there maybe another language barrier after 5.26.*?
Background
Since I use it rarely, a program update is the starting point when I reenter Perl. And that's why I was interested in studying the delta documentation before installing, and this delta was hard to find.