Vibers are losing their minds, but afaik reverse engineering binaries, let alone mere obfuscated JS, has been a thing pre-LLMs. Still, their closed source work was visible in higher fidelity than it was before.

Source (may be DMCA'd eventually): https://github.com/VineeTagarwaL-code/claude-code
Documentation for it: https://www.mintlify.com/VineeTagarwaL-code/claude-code/introduction
Python port (presumably not subject to copywrite): https://github.com/instructkr/claw-code