I don't understand what you are talking about "saved tabs data". If you are opening webpages from the "Bookmarks screen" those pages would be saved bookmarks. And if by "Bookmarks screen" you mean the Library window, those pages could be from browsing history. But neither contain Previous Session history. See if this support article helps you. https://support.mozilla.org/en-US/kb/how-do-i-restore-my-tabs-last-time