As highlighted by YANIS4224 over on Paste Bin (thanks, Gaming Reinvented), if you enter a specific combination of button presses during gameplay, you'll be treated to a single credits screen showcasing the developers responsible for engineering the N64 emulator for the GameCube release.
The button combination is an expansion on the classic 'Konami Code' cheat with which, if you've been around for as long as we have, you'll likely already be familiar.
It goes like this:
Press the following buttons while holding L + R + Z:
- dpad up
- dpad up
- dpad down
- dpad down
- dpad left
- dpad right
- dpad left
- dpad right
- X
- Y
- B
- A
- dpad up
- dpad left
- dpad down
- dpad right
- A
- start
It's a neat way of crediting the folks who worked hard to get Majora's Mask onto GameCube, and frankly it's incredible that we've gone so long without noticing it before.
The promotional disc on GameCube contained the original The Legend of Zelda, Zelda II: The Adventure of Link, Ocarina of Time, Majora's Mask, a demo for The Wind Waker, and a bunch of accompanying videos.