You have activated the Constants tab. All constants used in a mapping model of any pattern of the current model transformation are displayed. You can reuse them and place them via drag and drop in a mapping model.
The Constants tab is displayed only on the Transformation tab and exists only if a pattern of a model transformation is open.
If you select a constant in a mapping model it is also selected on the Constants tab.
The names of the constants of a model transformation are displayed in the Name column.
The column Pattern shows in which transformation patterns the constant is used.