As far as i can tell, it provides a toggle to Save Session, Clear Saved Session, and if you toggled Save Session on before exiting, you can click it again after restarting to reload *the single(?) window of tabs it saved.* idk, it never says, and I wasn't gonna look further at an add-on that 6 other tab mgr's can do with more control, features and instruction.

No way to save several session.
Edit: And it restores nothing!

To another user: "Why does it need to access the data for all websites???" Because it's the way it stores the URL.