Creative Commons BY-SA 4.0 International
Extra considerations:
BeepBox and JummBox are under The MIT License, and Zandro's OPL3 and OPL2 are under CC-BY-SA4, which is compatible with The MIT License (and GPLv3 as well, so you can use this SoundFont in anything GPL3-licensed. So yes, this bank is certifiably able to be a Linux package, even on distros like Trisquel that ONLY allow libre packages. Also, I have the bank on OpenGameArt for use in any games of the Liberated Pixel Cup variety, a game jam dedicated towards making FOSS games. This bank is also on other places besides this site, such as itch.io, OpenGameArt, IndieGameMusic, Archive.org, SourceForge, and others. And no, I didn't paywall the bank on ANY of the other sites it is on. I even point people to this site in the description to fulfill my CC-BY-SA4 obligations to attribute. I consider this SoundFont to be one of the best FOSS things I have done.) The William B. Santos stuff is Public Domain. OPLL stuff is libre. The Retro Player bank is under CC-BY 3.0.