You can hook up the CyberBrick core e.g. to Arduino MicroPython IDE (that uses also the REPL). By browsing the files, one can see that the stock CyberBrick code has 3 folders and a boot.py file, whereas the boot.py can be extracted and opened in a text editor. If a configuration has been added to CyberBrick core with CyberBrick app, you also have a file rc_config at the root next to boot.py. rc_config (w/o extension) is the same *.json configuration file that you can download from MakerWorld together with CyberBrick models or that you can create with CyberBrick app.
In the app subfolder there are two precompiled binary Python files: control.mpy and parser.mpy. In addition there is rc_main.py. The latter contains 198 lines of Python instructions that once again can be read with the help of a text editor. control.py and parser.py are both available in source form in the Cyberbrick official GitHub repository: CyberBrick_Controller_Core/src/app_rc/app at master · CyberBrick-Official/CyberBrick_Controller_Core · GitHub
The folder bbl contains 6 files: buzzer.py, executor.py, leds.py, motors.py, servos.py and __init__.py
All are extractable and human readable.
The last folder log contains by default an empty file logging.0.log.
When power is applied, first the boot.py executes that then loads ./app/rc_main.py. The app/rc_main.py loads the rc_config file (https://github.com/CyberBrick-Official/CyberBrick_Controller_Core/blob/b5fc07d44d65143cfef1164ae6234099fcb11d62/src/app_rc/app/rc_main.py#L86)
The RF communication between the CyberBrick modules and also the Bluetooth configuration interfaces seems to be in the frozen module(s). I wonder if ESPNow is being used for the communication between the CyberBricks in normal usage. Anyone with a logging RF spectrum analyzer, like Aaronia, who could have a look at this?