Development classes collect together development environment objects that can be considered as a unit and should therefore also be corrected and transported together. A development class can, for example, consist of a transaction or a group of related transactions.
See the section Working with the Workbench Organizer -> Development Classes -> Development Class Maintenance section of the BC - Workbench Organizer documentation for more about development classes.
If you want to create your own applications, you should define your own development classes. Your own development classes must begin with Y or Z. All other identifications are reserved for SAP standard classes.
Recommendation
SAP recommends that you use standard development classes if you want to extend existing SAP applications only.
Activities