This would be a bit easier to understand had the example used text that was unrelated to vim itself.

(seems to occur quite often with tutorials/documentation where the author has the topic they're showcasing top of mind, and naturally, but unnecessarily, uses the topic itself in examples, making it confusing for new readers to distinguish concept from arbitrary example)

For anyone wondering what's going on, "How do I\nexit vim?" is completely arbitrary text. This VimGraph function accepts this (or any other) text as an input, and shows the keys you could press to get from one place in the text to another using vim. The example limits the keys to just three (k, l, and w) presumably to not let things get too cluttered. (there's a curious 'crown' shaped key, which I suspect is a rendering bug where a 'w' and 'l' have been placed on top of one another).