The term "extra quality" isn't an official designation but a description of the file's characteristics and performance. An extra quality BIOS file means it possesses:
When he finally loaded it into the emulator, something was different. The "Sony Computer Entertainment" logo didn't just appear; it glowed with a crystalline depth Elias had never seen on his old CRT. The ambient "whoosh" of the dashboard sounded like a cathedral. He popped in a virtual disk of Shadow of the Colossus ps2 bios scph70012bin extra quality