Hello,
For Remote Desktop Services Client Access Licenses (RDS CALs), when they are activated and assigned to the system, the activation key itself is not stored directly on the server for viewing.
You can open Remote Desktop Services License Manager on the server to view the status of installed CALs. However, to see the specific activation key, you can refer to the documentation provided when you purchased the RDS CAL, or contact your vendor directly for confirmation.
I hope this helps.
Best regards
Jacen