Pretty handy. But the icon in the URL bar is pretty annoying, as these cant be removed. It is not nessecary, but when tiling the FF window in half the URL bar is nearly completely gone, which is not nice.

Permet de compartimenter certains sites dans des containers différents ( par ex. finances, paiements en lignes, réseaux sociaux ... ) étanches entre eux : un pas de plus dans la sécurité

very useful

Highly recommend this - great for managing multiple accounts (e.g. mail)

does the job! Improvement would be to create a new container tab from the context menu of a tab (right click on tab-title)