As bjh mentioned, Automation Studio sends compile binaries over to the PLC. You have to check a box to send down the source code (a feature that showed up AS 3.0). However, more recent versions of Automation Studio do have a "decompile" option that will work on many support file types, such servo drive parameter files. Also, you can monitor and modify the variables on a PLC in a watch window without having the source code.
Automation Studio does all PLC, servo, IO, and HMI programming/configuration for B&R product lines. There is Safe Designer for B&R Safe PLCs that is quasi-separate, but launches from within Automation Studio. If you are using B&R IO islands without a B&R PLC, you configure those with Fieldbus Designer, but I think they may have integrated that functionality into Automation Studio as well.
If the PLC is big and black, Automation Studio is not what you need. You probably need PG2000, a DOS only program. I don't know anything else about that besides that they are black gold on ebay.