The leak was posted on the
top page for Falcom staff on atwiki. An anonymous user added two Google Doc links on the bottom, including all the composer credits of FC/SC/the 3rd, Zero/Ao, Sen I/II/III, Nayuta, Tokyo Xanadu and Ys VI/Origin/Seven/Celceta/VIII, complete with detailed notes of the original composer/arranger and music codes. Honestly, I think it would be better to open a dedicated thread to the matter rather than bumping all the threads, but oh well.
Anyway, it's worth noting that Jindo is credited under Special Thanks in the game, thus being the only freelancer to work on Ys VI. Additionally, the Falcom Music Chronicle book set says that he "arranged" all the orchestral music for the FMVs in Ys VI, but the leaked credits actually confirm composition for these. Maiko Hattori should be added as an uncredited artist as well.