Actually it had been renamed to https://github.com/ArmageddonGames/ZQuestClassic for a while, before the repo got transferred to the ZQuestClassic organization.

What happened recently was Gleeok downloaded a source snapshot of the ZQuestClassic repo then uploaded it as an "initial commit" to ZeldaClassic/ZeldaClassic repo.

He could have easily just pressed the Fork button on the repo and automatically got a copy under his full control preserving the commit history in the process, as their repo is still fully public.

In addition, after forking, you can "detach" a fork by going to https://support.github.com/request/fork