Just the idea of how the bottom of the book, or reference section is a bunch of neatly named refactoring principles which follow a hierarchy/pattern. No specific ideas, Twas just a skim, but it was reminiscent of your lang hierarchy. One interesting idea for reference material like this could be taking full advantage of “sibling travel”. I don’t use that hotkey too much, I think it’s cmd + alt + bracket? As a quick way to look through the refactoring options