FFIII-(FFVI) intro theme unused instrument (SNES)
I found what is probably legacy data in the SPC engine for FFIII, a holdover from a previous game. It sounds to me like the chorus used in Secret of Mana. I just enabled it and you're hearing the result.
Other than the intro, thus far I have not seen this particular music sample in any of the other music for this game.
There is a second unused sample, but the tuning is completely wrong. Were I to fix the tuning, it would be another kind of orchestral string sample.