Thanks for the very fast update! I was not expecting that.
The single jex export may not be suitable for some but my backups are essentially insurance against total loss or for when I scrub everything down (including the sync target) and start again in order to clear out too many "orphaned" files. Being able to dump everything back in in one go is a great benefit compared to doing it notebook by notebook.
Also having the css files included means that all the main customisation files can now be protected.
I can't thank you enough for doing this. It's a feature I have always wanted Joplin to have.
I am now having a look at your Note Overview plugin which seems to be an clever way of maintaining automatically updated saved searches.