... it handles correctly the interesting part ...

But it handles the incorrect part in a confusing and misleading way.

... and ... helps a lot in spotting the wrong part.

Whether it helps "a lot" or at all is open to question. But why not just fix the wrong part? Please see How do I change/delete my post?. (Of course, I'm suggesting changing your reply, not deleting it!) Perhaps also mention that YAPE::Regex::Explain only supports regex features added through Perl version 5.6.