This is meaningless without knowing the contents of PROMPT.md. The blog post hides the contents of PROMPT.md in a second subscriber-only post (I don't know if the post's 36 minute video explains anything - 33% in it still hasn't).

https://github.com/repomirrorhq/repomirror/blob/main/repomir... (discussed in https://news.ycombinator.com/item?id=45005434) provides a bit more detail, and prompts, but only seems to use the method for porting existing software.