Use the primary parameter with admin show_connections to display information on all primary connections.
admin show_connections, 'primary'
Connection Name Server Database User ---------------- ---------- --------- ---------- SALES_DS.pdb SALES_DS pdb pdb_maint SALES_DS.pdb_conn2 SALES_DS pdb pdb_maint
SALES_DS.pdb is the default connection between the Replication Server and the pdb database of the SALES_DS data server because the connection name matches the combination of the data server and database names.
SALES_DS.pdb_conn2 is an alternate connection between the Replication Server and the pdb database of the SALES_DS data server because the connection name does not match the combination of the data server and database names.
Optionally, use the rs_databases system table to list both default and alternate connections to the Replication Server.