Choose a .mid file and this page will produce a Scratch 3 .sb3 project that plays the notes (using the Music extension) when the green flag is clicked.
Notes about limitations
Supports basic MIDI files: extracts Note-On/Note-Off events and converts them into sequential play note blocks.
Tempo changes and complex multi-track arrangements are simplified: the converter uses the first tempo it finds and flattens tracks into one stream.
This generates a minimal Scratch project.json and packages it into an .sb3 file. It may not preserve instruments or simultaneity perfectly; it's a good starting point.