Ah, sorry. I remembered people at the time of its release saying it was Dolphin because some of the bugs were identical. I guess I misremembered that speculation as fact. I didn't even know Dolphin was GPL. Thanks for correcting me.

There might also have been some confusion because the Gamecubes official codename was Dolphin, so Nintendo's emulator may well have the string "Dolphin" in it despite having nothing to do with that Dolphin.