SQLite is a fine single-file application file format, but if you want average users to be able to inspect and perhaps fix application data when things go wrong,

SQLite is a fine single-file application file format, but if you want average users to be able to inspect and perhaps fix application data when things go wrong, a tree of JSON-format files is more friendly. True, this requires care to ensure that such files are updated reliably, but that's not quite rocket science.