https://addons.mozilla.org/en-US/firefox/addon/tree-style-tab/ https://addons.mozilla.org/en-US/firefox/addon/tree-style-ta... yep. I don't know if it will cle

https://addons.mozilla.org/en-US/firefox/addon/tree-style-tab/ https://addons.mozilla.org/en-US/firefox/addon/tree-style-ta... yep. I don't know if it will cleanly update; so it may lose your settings. (Webextension ports have to spend one release in "hybrid" mode where they'r a webextension wrapped in a legacy extension shell to port settings correctly)