It appears to be fairly active on GitHub, with several commits per day: https://github.com/PCSX2/pcsx2
The PS2 architecture is implemented in the open source PCSX2 and plays "over 98% of the official PS2 library is considered playable or perfect". Amazing feat and well worth trying out: https://github.com/PCSX2/pcsx2 and check the Wiki documentation https://wiki.pcsx2.net/PCSX2_Documentation
I had a read through the PCSX2 emulator recently, that was quite interesting: https://github.com/PCSX2/pcsx2 it's a complex project in what was surprisingly readable C++ code.