Originally used by 3D Realms as the "release date" for the game Duke Nukem Forever, it basically just translates to either "we don't know yet" or can be jokingly used in the context of indefinitely delayed/Early Access games.
When a project or product is in the developmental stages. It has no set time line given, and is a work-in-progress. The moment the finished project or product has been finalized, then that is when it has been completed. It will be done.