The Maker Room is a "blank slate" room, which is useful when you want to create a Custom Room with the Maker Pen from scratch. It can only be entered by creating, joining, or being invited to a Custom Room of this type. It shares this feature with the Performance Hall and The Ink Space.
The Maker Room is a simple, rectangular room. The special feature of the room is that its walls, ceiling, and floor can be deleted with the Delete mode of a Maker Pen. Once any of the walls are deleted, you cannot bring them back; therefore, it makes sense to freeze (with the Freeze mode) all the walls that you want to keep as soon as possible in order to avoid that you accidentally delete (or move) them.