Great idea overall! However, I think it makes more sense to add extension popup functionality, which will reveal headers list on click, rather than having constant sidebar on the left. Also, it doesn't adapt to browser theme and oftenly picks wrong headers (for example, page footer's buttons).

At first the addon didn't work for me.
I got this error message :
"missing host permission for the tab"
When I restarted Firefox (go to about:profiles), a nice overview of the page structure appears in the sidebar
I think I'll find this a really useful add-on.
>> Oh Yess ! It is REALLY useful. Can I give it 6 stars please !
Thank you Damien for your work.

Thank you Damien. Please consider applying Firefox Dark Theme: https://gitlab.com/DamienCassou/overview/-/issues/3.

Yay! Exactly what I was looking for as a replacement for HeadingsMap (that was discontinued after the transition to Web Extensions). Thanks a lot for taking the time to make this!