From MozillaZine Knowledge Base
In order to make sure users see the end-user license agreement when the EULA changes, Mozilla keeps track of which EULAs have been accepted. This preference records whether the given version of the EULA has been accepted.
Possible values and their effects
The EULA version specified has been viewed and accepted by the user. If the version is the same specified in browser.EULA.version, donâ€™t display the EULA again.
Display the EULA for the userâ€™s acceptance if it is the same as the one specified in browser.EULA.version.
First checked in
Has an effect in