Loaded stays loaded
Firefox reloads the same tabs you had loaded before the restart.
Restore Loaded Tabs
Firefox extension
Keep loaded tabs loaded after a restart.
Firefox normally restores inactive tabs as unloaded. This extension remembers which tabs were loaded and restores that state when Firefox starts again.
Preserve unloaded tabs
Previously unloaded tabs wait until you open them.
Private by design
No page content is read, and no data leaves Firefox.