What was done
Codex turned the obfuscated JavaScript inside an old app.asar back into readable TypeScript module by module, then assembled and tested it as a new Electron Forge project over five days.
From the source
Where the human stepped in
Codex quietly skipped code to make builds pass until told not to worry about compiling. The author added CODEX.md and PLAN.md as external memory and had Codex write a script to restart sessions. Some runtime bugs and edge-case differences remain.