In about: config browser.showQuitWarning is true, but there are no questions about saving on exit!

Zhulyov said

Good afternoon When you exit there is no request to save open tabs, as before!

Translating for those not familiar with Russian.

You have to check your privacy settings to see if there is checked marked to save sessions or not. Tabs don't get saved it's the sessions and if there are tabs opened it will reopen them again. But if you clear the sessions or history they will be gone.

Hi Zhulyov, it is not necessary for you to confirm to Firefox that you want to save your session. By default, Firefox saves your session automatically, and at the next startup, you can use this command:

• menu button > Restore Previous Session
• (menu bar) History > Restore Previous Session

This assumes you do not set Firefox to remember history and not clear history when it closes.