Looking back I found this asking for XF export
https://www.pgmusic.com/forums/ubbthreads.php?ubb=showflat&Number=6026

I looked at a midi file with the XF chords
PSRUTI Chord and Lyric Protocol
File: C:\Users\Band In A Box\Downloads\test.mid

[start chords+lyrics]
Chd 002:01:000 Bb
Chd 002:03:000 Fm7
Chd 003:01:000 Ab7
Chd 003:03:000 C#M7
Chd 004:01:000 Ebm
Chd 004:03:000 F7
Chd 005:01:000 Bbm
Chd 006:01:000 A#
Chd 006:03:000 A#
[end list]

If I can find these in the Midi file I can read them out or write them to.
I can read this info in Reaper and then I could record or write to midi.
This way I could send the XF chords to the keyboard while using the BBPlugin. The BBPlugin can transfer it's chords to Reaper and vice versa.
PG writes it's chords to the midi file like Yamaha, I just need to find where Yamaha writes them in the midi file.
I don't know if that's like what you want to do ?

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Yamaha-XF-Chords.png (5.42 KB, 113 downloads)