containing the project.json and assets. Right-click the file and select "Rename." Change the end of the filename from .zip to .sb3 . A warning will appear asking if you’re sure; click Yes .
Scratch expects DEFLATE compression (standard ZIP). The converter repackages the folder, ensuring no extra MacOS metadata ( __MACOSX ) or hidden system files slip in—common causes of “Invalid project” errors. Zip To Sb3 Converter
rokcoder-scratch/sb3-commit: Set up for automating ... - GitHub containing the project
For those who need to ensure the project.json is formatted correctly during the conversion, tools like the or Turbowarp packagers can help "wrap" assets into a compatible Scratch file. Pro Tips for a Successful Conversion Zip To Sb3 Converter
Here are the primary features you would expect in such a tool: