I understood the docs so that Bluetooth on PC is only supported through the special USB Buetooth Dongle from Makebot. The regular Bluetooth interface is only supported on Android and iOS.
My Linux Laptop does also detect the Codey via Bluetooth and I can pair with it. But there is no virtual COM port as usual on other robots.
The USB cable provides a virtual COM port when the CH340 driver is loaded. The official driver download site of the chip manufacturer is http://www.wch.cn/download/CH341SER_ZIP.html. In Linux you do not need to install a driver, it’s already included in the Linux Kernel.