This is the official method to detect whether your project is running in TurboWarp or forkphorus. There's also blocks to detect specifically TurboWarp or forkphorus. See inside for more information. https://turbowarp.github.io/#414716080 https://forkphorus.github.io/#414716080 Other Scratch compilers are welcome to implement this. Thanks to @Executec for the idea of using boolean arguments.