Good replacement for the TST. I would like to see the possibility to highlight not only unloaded but also unread tabs.

How to apply custom theme?

Odd that it doesn't change the actual tabs' positions when they're reordered in the trees, and occasionally a tab doesn't show up in the tree.
However, I'll absolutely take it: it's the only thing I've tried so far that preserves my "select multiple tabs, put them in another window" workflow from google chrome.

I'm excited to have vertical tabs that are collapsible and configurable as a web extension! Let people know how they can contribute! I am so dependent on tree-style tabs. Thanks very much.

I'm a long-time fan of the Tree Style Tab extension, but with the coming end-of-life for legacy addons, I decided to try out a WebExtension option. Found this extension via Reddit, and while I agree with previous reviewers that it is still limited (especially the fact that it has zero effect on the native tab bar), as others have mentioned that's more the fault of the in-progress WE protocol than the developers. It does the most important thing, which is let me view all my tabs in a vertical tree.

Just make sure you have the side bar visible, or you won't see your tab tree. Took me an embarrassingly long time to figure that out. :)