“Flutter apps can work on Android, iOS, Windows, Linux, and Mac OS, and the Flutter UI and rendering engine, included with every app, translates everything to the OS layer.”
The Oxford comma before “and Mac OS” means that one can’t easily discern the end of the list. If, instead, it read “…Windows, Linux and Mac OS, and the Flutter UI and rendering engine,“ one would know that the Flutter UI and rendering engine were not part of the list but a separate clause.
