Forking creates your own private copy of a Code Card.
From a published card, select Fork. Code Card creates a new private card in your account and places it in My Cards.
The fork keeps a reference to the card it came from, but it becomes your own account-managed card. You can edit it, test it, add it to collections, and publish it independently.
When a public card is open in the editor, you can also modify the code temporarily and fork the code currently in the editor.
The original published card remains read-only to you unless you are its owner.
If the original card is later unpublished, an existing private fork remains in the fork owner's account.