There has been a case when AI bot suggested one of my users to reinstall my addon to solve some issues, which of-course deleted all data stored inside.
What options do we have for local backups that can survive re-installation?
I’m looking for a (semi)persistent, fully automated solution, something that could get deleted eventually, but would be available at least some time after reinstalling addon.
Let’s say I need to store up-to 400KB of data and I have <all_urls> permission.
I was thinking opening about:blank page and store the data in the localStorage using content script, but it looks like that won’t work:
Maybe I could “misuse” like this some other origin, like example.com? 
(ok I see now that this would be absolutely terrible idea since apart the host, also other extensions would gain access to the data, so I would have to encrypt it with asymmetric encryption…)
UPDATE:
The more I think about this, the more I realize the best solution is to remind users to backup their data.
There are also other events that can destruct data, like broken SSD or lost notebook.