If you see project.json , the conversion succeeded.
Rename-Item -Path "oldfile.zip" -NewName "newfile.sb3" convert zip to sb3 updated
Usually, creators convert to ZIP to manually swap out high-resolution assets or to debug the project.json file. You must convert it back to .sb3 for the Scratch offline editor or the online website to recognize and open the file. Method 1: The Manual Extension Swap (Fastest) If you see project