ao3 saver

Storage of fics with the AO3 saver on other devices

In the description, it says anything you view is only kept on your local device. So, if I get a new Chromebook and have to install this app on that, will I have to save all of my works again? Can I not install this app on my phone? Can this app be synced with other devices so whatever data I save on my Chromebook is available on my other devices? Can you make this app available on phones?