sidebar-switch
A switch for Firefox's native sidebar (bookmarks, history, etc). It's a slim vertical button on left of main content.
Replace the legacy addon All in One Sidebar. You can open sidebar by clicking edge of screen.
This is a Firefox userChrome JS script.
Tested on Firefox 78.
How to enable
This repo only contains the specific function, doesn't contain the code to enable userchrome script.
For how to enable, see