Off topic: this NN-512 site has good UX for having no CSS/JS (I know, many of you would claim it's because those are omitted...). Did you use some kind of site generator?
The anchor tags for the listings go to top instead of being self-referencing. Is that a bug?
Like
format = `<h3 id="%d"><a href="#0">%s</a></h3>` +
format = `<h3 id="%d"><a href="#%d">%s</a></h3>` +
Hm. I guess the web has programmed me differently. Say I'm CTRL-F searching through the page and I notice an interesting bit of code and say "Hey I have a question about this". Then I start looking for a shortcut to that one file and assume that shortcut is the nearby <h3> header. I expect this because I've seen this pattern implemented a lot. You could have the <h3> be that local anchor and a short [top] link next to it.