The onboard micro-USB connector (j6) provides access to the USB block of the PSoC 5LP device. This connector enables you to develop USB applications. Please check File- > Code Example and USB related example codes,i f you are interested in USB examples. If you want to program/Debug the device, Kitprog USB can be used.
Let me add some more to Vasanth-san's information.
So as you can see, there are two USB connectors
(1) is connected to the KitProg's CY8C5868LTI-LP039 and this part is working as an ICE and a debugger aka KitProg.
KitProg is connected to the target CY8C5888LTI-LP097(target) via SWD (single wire debugger) and UART.
So from a user view point there are connections
PC -> KitProg -> CY8C5888LTI-LP097
and using PSoC Creator and/or other tools we can program, debug, and use the UART of target through this KitProg.
(2) is connected to the USB module of the target.
If you want use USB module in the target this connector is the USB port you can use.
So unless you prepare some USB application in the target, the port will not be detected/visible from the PC.