To answer rest of your question, we are using official sqlite (via evolu). We don't have a fallback for opfs. But opfs seems to supported in most browser. https://developer.mozilla.org/en-US/docs/Web/API/File_System... Although, seems like the private mode in Firefox is related to opfs, so we might not be able to solve it. But again, most users won't use the app in private mode.