Sb3.zip -

If your goal is to add a new functional block inside Scratch itself: You must develop a Scratch Extension using the Scratch VM.

An is actually a ZIP archive used by Scratch 3.0 to store project data, including code (in a project.json file) and media assets like sounds and images. sb3.zip

Once compiled, the extension's data will be stored within the project.json whenever the user saves their project as an .sb3 . If your goal is to add a new