Container Tabs Sidebar by Maciej Mionskowski

A Firefox Addon that shows currently opened tabs in a sidebar grouped by a privacy container.

Usage
In order to open the sidebar click F2 button on your keyboard. If it doesn't work then open any sidebar (eg. using Ctrl+B), and change the sidebar via dropdown menu.

Customization
In order to customize your experience with ContainerTabsSideber, this addon provides a settings page, which can be accessed by going to Addons (Ctrl+Shift+A), selecting ContainerTabsSidebar and clicking preferences.

You can also hide original tab bar by following this resource: Firefox Appearance Modifications

Links
Source code