The midi-instrument type defines MIDI 1.0 instrument playback. The midi-instrument element can be a part of either the score-instrument element at the start of a part, or the sound element within a part. The id attribute refers to the score-instrument affected by the change.
The
<midi-instrument>element.The midi-instrument type defines MIDI 1.0 instrument playback. The midi-instrument element can be a part of either the score-instrument element at the start of a part, or the sound element within a part. The id attribute refers to the score-instrument affected by the change.
See
https://www.w3.org/2021/06/musicxml40/musicxml-reference/elements/midi-instrument/