Firefox uses SQLite for a bunch of internal data and the bindings are accessible to extensions. So basically Firefox is a cross-OS platform that's guaranteed to be linked against SQLite, with public bindings.
It probably works better than many of the Java-based 'cross-platform' solutions to many problems...
Mozilla took a stance against WebSQL because there was essentially no "standards specification" for it. The standard has rather been defined by its implementation: SQLite. Obviously, this SQLite is a very pragmatic solution, but Mozilla wasn't just happy with something that couldn't have an alternative and therefore permanently constrained. Instead they implemented [IndexedDB](https://developer.mozilla.org/en-US/docs/Web/API/IndexedDB_A...), which is an open standard. However, indexed DB is not a relational SQL store and is therefore less familiar to developers. Instead, it is transactional indexed key-value store on which it is possible to develop an SQL or other type of store.
Firefox uses SQLite for a bunch of internal data and the bindings are accessible to extensions. So basically Firefox is a cross-OS platform that's guaranteed to be linked against SQLite, with public bindings.
It probably works better than many of the Java-based 'cross-platform' solutions to many problems...