Where do the intro pages for the each Challenge Section reside?

I saw that the Intermediate Coding Challenges introduction page is a stub. I wanted to add a little text to make it better but I can’t seem to locate it in the repo. Can someone point me there?

I found them, navigating to freecodecamp/guide/<your-language>/certifications/<your-module>/<your-submodule>/index.md

E.g. in this case it is: