The Wikipedia articles are confusing and/or very vague. "Garbage collection (computer science)" defines garbage collection as "a form of automatic memory management." (The rest of the article is about garbage collectors.) The same article also calls reference counting a form of automatic memory management.

"The garbage collector attempts to reclaim garbage, or memory used by objects that will never again be accessed or mutated by the application." further confuses the issue, since garbage never exists in Perl according to that definition. The memory is freed as the point where it would become garbage.

But that's all irrelevant here. It's clear it considers reference counting a type of garbage collection. I was led to believe GC refered specifically to asynchronous memory reclamation, but that's apparently false. My post has been corrected.