Enhancement Builder
The Enhancement Builder is a tool for creating and managing enhancements which is fully integrated into the ABAP Workbench. You cannot use a transaction code to call it directly.
Besides defining enhancement options for repository objects which can be enhanced within the enhancement concept and the related actual enhancements, you can edit enhancement spots and enhancement implementations in the Enhancement Builder.
More information:
Creating, Editing, and Deleting Enhancement Spots
Creating, Editing, and Deleting Enhancement Implementations.