Thanks for sending that along (so fast, too)!
Looking inside the MIDI file, there is
very little information besides the notes. This is an exhaustive listing:
Track 0- Sequence Name: MIDI out
- Tempo: 60 bpm
Track 1- Track name: VOICE
- Instrument name: VOICE
- Change channel 1's instrument to: Violin
- ... followed by 292 "Note" messages on channel 1.
My guess is that Presonus hasn't spent much effort on Notion's MIDI export capabilities. They clearly have that extra information available to them but aren't saving it out to the MIDI file.
If Notion has a different export format available (say, MusicXML?) you may be able to add an intermediate step like loading it into
MuseScore and exporting it as MIDI from there instead. MuseScore's MIDI exporter keeps the key signature information intact.
(If Notion supports MusicXML, the good news is that we're adding MusicXML support to Synthesia in version 11.)