Tab Session Manager basically saves copy of your windows or groups of windows whenever you close them, or on demand, for you to summon back whenever you need them. It's a really great add-on for people with tons of tabs and windows! The interface is a bit aggressive with its popup asking for donations, but it's fine otherwise!

My only request is that I'd massively prefer a sync option with my Firefox account over the provided Google drive option. In corporate environments, it's not always an option to use Google services! Changing this would get my review up to five stars.

This is one of those essential addons that you just must have, no questions asked. I configured it to auto-save the tabs every 30 minutes. It has already saved me a lot of time and headaches when I experience crashes, and the browser can't always recover the last session by itself.
Thank you Sienori!

I get some problem , when i Enable Synchronize Function to google drive , i didn't see any .json file in there , where they go ?

Great work👏

It's a mess. When you restore session, it DOES NOT restore the session, but ADDS windows and tabs to the currently open ones.

Suppose you have 10 windows and saved the session. Then later on you navigated to some other URLs. Now you want to restore the saved session. But after you click on restore, current windows will NOT be closed, but new windows will be added. Now instead of 10 windows you have 20. If you activated autosave and restore a newer version later on, you will have 40 windows, then 80, then 160, etc. Each windows will be duplicated 4, 8, 16 times etc.

I don't see any option to disable this awkward mode.

Having this awkward mode makes the extension unusable.

Since some weeks ago, it's not saving on browser exit. Still a good manager.

Works great except that it constantly updates, then announces its update all over my browser (opening tabs and all this stuff). What's worse, it needs to confirm permissions after every update, or the sync stops working. But it doesn't ask to confirm permissions, so the sync just stops working! Extension developers need to make some effort to understand how these things work, and should also be using their own extensions so they learn what goes wrong all day every day in the user's browser.