It took some iteration and hands on testing to get that right across multiple operating systems. Also to pass shellcheck, etc.
Even if an LLM -could- do that sort of thing as well as my team and I can, we would lose a lot of the arcane knowledge required to debug things, and spot sneaky bugs, and do code review, if we did not always do this stuff by hand.
It is kind of like how writing things down helps commit them to memory. Typing to a lesser extent does the same.
Regardless those scripts are like <1% of the repo and took a few hours to write by hand. The rest of the repo requires extensive knowledge of linux internals, compiler internals, full source bootstrapping, brand new features in Docker and the OCI specs, etc.
Absolutely 0 chance an LLM could have helped with bootstrapping a primitive c toolchain from 180 bytes of x86 machine code like this: https://codeberg.org/stagex/stagex/src/branch/main/packages/...
That took a lot of reasoning from humans to get right, in spite of the actual code being just a bunch of shell commands.
There are just no significant shortcuts for that stuff, and again if there were, taking them is likely to rob me of building enough cache in my brain to solve the edge cases.
Also yes, I only use FOSS tools with deterministic behavior I can modify, improve, and rely on to be there year after year, and thus any time spent mastering them is never wasted.