This was probably a good extension as of the last update (3 years ago). Now it's abandoned, unmantained, obsolete and maybe even dangerous.

The list of domains has a terrible layout with misplaced scrollbars, very difficult to navigate.

It also requires the following two flags:
* privacy.userContext.enabled
* privacy.userContext.ui.enabled
that I cannot remove in order to disable the useless "container tabs" feature.