This isn't applicable to scheme as a config format, but some config formats are line based and have programmatic tools to manipulate them, e.g. the .ini-like fo

This isn't applicable to scheme as a config format, but some config formats are line based and have programmatic tools to manipulate them, e.g. the .ini-like format Git uses, try adding some comments to ~/.gitconfig and manipulating it with `git config --global <...>`, it'll all be preserved. You will lose any comments like this though: [user] name = My Name ; that's my name! Programming is hard in the face of arbitrary user data.