I just had to start using a new laptop given by my office. I had at least 30 tabs open in my old laptop. I just needed those open tabs in my new laptop too (opened).
Using sync did not solve my problem. Sync just helped me to sync my history, bookmarks but did get my “open” tabs be “open” in my new firefox.
Copying the sessionstore.js from my firefox folder to the new one fixed the problem.
I just scp’ed the sessionstore.js from my old laptop to the new one.
$ scp ~/.mozilla/firefox/mye4weo0.default/sessionstore.js hostname:/home/username/.mozilla/firefox/mye4wad0.default/sessionstore.js
I got all my open tabs opened my new firefox🙂