If you go to Help > About Firefox when there's an update to be installed, there's a restart button that restores tabs. As for memory leaks, it's been a project

If you go to Help > About Firefox when there's an update to be installed, there's a restart button that restores tabs. As for memory leaks, it's been a project for a while now: https://areweslimyet.com/ https://areweslimyet.com/ I'm not entirely sure what the third point is referring to (I just let the browser handle cookies), but in the Privacy tab of Options, you can view and remove individual cookies and search by site. So maybe that helps with what you want?