Is this in your iCloud? If so then it is just the Message toggle that is used almost strictly to sync your messages between your Apple devices… since I only use an iPhone and nothing else I turned it off and elected to delete the backup(Normal Messaging Backup Doesn’t Use iCloud Space) so in 30 days it’ll be permanently deleted by their servers. If you go to iCloud-Manage Storage-Messages-Disable&Delete you’ll be fine and still get messages backed up to your account. It just won’t show in your iCloud and messages wont sync between devices. Only way to rid THAT file though IS to delete the whole file itself AFAIK.