Yeah Media Bay writes everything to metadata in the file. I cant count how many times I’ve wiped out my entire MediaBay installation and reinstalled it, I still have files I tagged 4 years ago showing tempo and key…
If the files themselves were tagged properly, Media Bay should be picking some of those up but it seems hit or miss. I have a few Zero-G sample packs in WAV format from when they started adding ACID metadata and turning them into Kontakt libraries. The ACID files all show tempo and key as they came. But my AMG 160db library I bought 20+ years ago is an old ‘Apple Loops’ release that does not.