From MozillaZine Knowledge Base
Previous to Firefox 0.9 and Mozilla Suite 1.7.5, the meaning of the current preference network.cookie.lifetimePolicy was stored in three preferences: network.cookie.lifetime.enabled, network.cookie.lifetime.behavior, and network.cookie.warnAboutCookies. This preference controls whether the deprecated preferences should be migrated to the current preference.
Possible values and their effects
The deprecated preferences have been migrated.
The deprecated preferences have not been migrated. Migrate them, then set this preference to true. (Default)
First checked in
Has an effect in