SQLite is also part of iOS and Android.
Shipping a New Mindset with SQLite in Windows 10 | Engineering @ Microsoft
"How do you ship over 200 Data Access APIs that work across half a dozen different types of devices and have a 100% test coverage, but with only a couple of days of engineering effort? It’s simple, you ship SQLite. Over the last year, Windows engineers have worked closely with the amazing SQLite Core Development team led by Richard Hipp to bring SQLite, the popular open source database engine, to Windows 10."