For me, it is also a superior alternative to Tree Style Tab on Firefox. It has better keyboard shortcuts, and drag and drop support of tabs or entire subtrees i

For me, it is also a superior alternative to Tree Style Tab on Firefox. It has better keyboard shortcuts, and drag and drop support of tabs or entire subtrees is more reliable than TST. Unloading entire subtrees and restoring them on other computers is also a nice feature that I don't want to miss anymore. The extension is closed source, and its dev sometimes needs a few weeks for important fixes, but it is still one of my most favorite browser extensions out there.