Here we would like to draw your attention to SA21 transaction code in SAP. As we know it is being used in the SAP BC-SRV (Basis Services / Communication Interfaces in Basis) component which is coming under BC module (BASIS).SA21 is a transaction code used for Customizing Regional Structure (BAS) in SAP.
It comes under the package SZAD.
Transaction SA21 technical data table
|Purpose||Customizing Regional Structure (BAS)|