[jjuran]

It's mostly checking Gestalt() and scanning the unit table for specific graphics drivers, occasionally peeking in low memory. (My own v68k core identifies itself through undefined CCR bits in the CHK instruction.)

Have a look at tools/mac/system-info/system-info.cc and mac/libs/mac-sys-utils/mac_sys/has/virtualization.hh in the metamage_1 repository.