SNESoid code: https://github.com/Pretz/SNesoid/tree/

This is the stuff that is under a non commercial license that he is selling.

The readme also links to a sourceforge account with all the code yongzh has released. What's there is frequently outdated and some emulators (n64oid) are outright not there.

The issue here seems the same for all the mentioned emulators, while he have developed a common lower layer graphic library for them, the actual emulation code is from other famous open-source emulators (original project or ports, all with non-commercial licenses). E.g. snesoid is based on a snes9x port.

Anyone with a G1 or G2/Magic will remember when all the yong's emulators suddenly appeared on the market nearly two years ago, at the same time he published nes/snes/gba/mame emulators. Considering the time needed to develop a single platform emulator that supports a good share of games (usually years, maybe with few exception in the history of console emulation), developing them all from scratch would have been impossible imho.