Ok, So. The Drawing App Posted by oleksiitwork on Tuesday August 09, 2022 @10:52AM from the trekhleb.dev dept. https://trekhleb.dev/blog/2022/okso/ ( 5 comments | on HN )
Sorry, don't want to make HN comments to be a GitHub issue tracker, but this info will help.
It looks like F.F. doesn't support IndexedDB in private mode at all: https://bugzilla.mozilla.org/show_bug.cgi?id=781982, and IndexedDB is the main data storage for okso.app.
If this is the case I'll think about some fallbacks, maybe to LocalStorage, to make the app work in such cases as well...