It seems it only supports CDC and some JTAG mode. For keyboards and such, the USB stack should support HID which doesn't seem to be the case here. In other words, they've implemented a USB 1.1 FS stack just so far to make intermediary USB2UART chips like FTDI and CP2102 redundant.
I doubt they implemented CDC in hardware.
If they have a low-level USB peripheral, all the high-level protocols you want can be implemented in software.