Outliner

Simple, but that's good when you have very large documents to outline, and other outliners are too slow.

I think Turbo Outliner is better and quicker, but it too lacks options. HeadingsMap is even more accurate.

breaks page https://css-tricks.com/the-lengths-of-css/#article-header-id-11

Brilliant.

This is excellent - aside from it working as desired, the aesthetics are great.