Browser.sessionstore.resume from crash
From MozillaZine Knowledge Base
Firefox 2.0 introduces a built-in Session Restore feature, allowing the user to continue browsing from where they left off if browser restarts. This preference controls whether the last saved session is restored the first time the browser starts after a crash.
Possible values and their effects
Restore the previous session when the browser starts after a crash. (Default)
Do not restore the previous session.
First checked in
Has an effect in