This Soundfont is a fixed version of Micasddsa4000's Jummbox Soundfont. I, stgiga, fixed the pitch and mappings, and also added OPL4 drum parts to Zandro Reveille's OPL3 drums (TheFatMan is part of the equation, including OPL2 booster drums too) because Micas didn't use drums. It's really neat and retro!
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. The YRW-801 OPL4 samples aren't likely free.