Curl and SQLite are my favourite examples of properly engineered, rigourously tested _anything_. It's really philosophical - those projects' contribution requirements demand such rigor, and the maintainers stand by that demand. A non-load-bearing document (not project code) is what makes that possible - very reminiscent of Einstein's thought experiments leading to tangible projects such as GPS or Descartes's belief that all problems can be solved through rational thinking.

Some people must be working on training some models exclusively on high quality OSS code base like curl and SQLite without the noise of low quality training data.

I would do that with 100% local models from scratch.