And note: Signal has been misleading users about options for iOS backups for a decade! In September 2015, users were told it was "on the roadmap": https://github.com/signalapp/Signal-iOS/issues/905#issuecomm...
No option has ever existed on iOS, despite the recent announcement assuring users "Local backups still exist". They've never existed for iOS users!
If you are alleging that Apple's own local Finder/Itunes backup of an iPhone includes Signal messages, that's not true, against reasonable user expectations, by Signal's own design choices.
Anyone who's counting on such local backups to save their histories is in for the same rude surprise I and many others have hit unaware:
https://www.reddit.com/r/signal/comments/1hgukpg/backup_and_...