>>843
設定しないよりましかも、っていうのならあった

// Whether to delay popup notifications when an update is available and
// suppress them when an update is installed and waiting for user to restart.
// If set to true, these notifications will immediately be shown as banners in
// the app menu and as badges on the app menu button. Update available
// notifications will not create popup prompts until a week has passed without
// the user installing the update. Update restart notifications will not
// create popup prompts at all. This doesn't affect update notifications
// triggered by errors/failures or manual install prompts.

pref("app.update.suppressPrompts", false);