Serial Wire Output (SWO) support means support for a single pin output signal from the core. The Instrumentation Trace Macrocell (ITM) and Serial Wire Output (SWO) can be used to form a Serial Wire Viewer (SWV). The Serial Wire Viewer provides a low-cost method of obtaining information from inside the MCU.
Usually it should not be necessary to configure the SWO speed because this is usually done by the debugger.