My very last comment ;). Standard not as in POSIX, but related to a group of software: [rocketmouse at archlinux ~]$ pacman -Qi dssi lv2 | grep License Licenses : BSD LGPL Licenses : ISC BSD and BSD alike side by side with the GPL. Btw. I'm in favour of audio units https://developer.apple.com/documentation/audiotoolbox/auaudiounit .