Using rshell I've managed dump the micropython filesystem of my hub after updating it to
connect serial /dev/ttyACM0 115200
rsync -a /pyboard ~/spikefw
Note: These commands are for linux.
(I also managed to partially dump the initial version on the hub
v0.5.01.0000-42a938e, but ran into issues with binary files as I was using ampy at the time.)
I've not found any online resources for the micropython filesystem or the firmware of the SPIKE Prime hub.
Interestingly it seems the the initial version I have
v0.5.01.0000-42a938e is comprised of the micropython source code (*.py files) whereas the updated version
v1.0.03.0034-c3879ab only contains pre-compiled micropython bytecode (*.mpy)
The license file included with the micropython code, and the headers in the files, state that the code is licensed under the MIT license, so I've uploaded it to my github please feel free to PR more versions.