You can enable them right now by setting sidebar.verticalTabs = true in about:config

Why can’t humanity seem to learn that storing all of our knowledge and cultural artifacts in just one place with no backup is a BAD IDEA? Don’t let the library of Alexandria burn again!

Nope

At what point when accumulating grains of sand do they become a heap?

There is no rule. It just is whatever it is.

xtract ze vucking file