Converting a file to an SB3 format is essentially just a matter of renaming the file extension , as SB3 files are actually compressed ZIP archives containing Scratch 3.0 project data. Why Convert ZIP to SB3?
If your project is currently a full of files (like project.json and various images), you need to package them back up correctly. Open the folder containing the project files. convert zip to sb3
For the renamed .sb3 file to work in the Scratch Editor , the internal ZIP structure must include: ZIP Converting a file to an SB3 format