I believe that you may have inquired all of my reviews in each one form!

唐突に保存してたタブが全部消えました。
まだ無事な方はすぐにエクスポートしてください。
All of my saved tabs suddenly disappeared.
If yours are still intact, export them immediately.

very useful for when you wanna shut the pc down but still save your tabs !
be aware tho to not save tabs for years tho , it's meant to be temporarily .

Works, even together with Tab Stash and Tab Containers. Just be careful about updating in macOS, I read that you might experience problems.

It finally happened... Multiple months worth of tabs instantly gone, the addon froze up and the extension menu for saving tabs wouldn't work, I close Firefox and then its completely empty. This extension hasn't been updated in a long time as well, I think it's time to find an alternative.