Inside it, you'll see something like rmmzsave.12345678.file3.
The Game ID is 12345678.
How does it work?
PC to Web: Converts loose files from your computer into a single aggregated `.json` script block payload.
Web to PC: Reverse engineers your backup `.json` save matrix file directly back into individual `.rmmzsave` assets compiled inside an easily extractable `.zip` archive pack.