Well here's a super interesting discovery! Some fans have stumbled upon an F-Zero X developer cartridge, and tucked away inside was a 1997 beta build of The Legend of Zelda: Ocarina of Time. As you might expect, the build is filled with all sorts of content that didn't make its way into the final game. Graphical changes, text tweaks, different fonts, and so much more! You can see some of the discoveries in the video above, and keep track of all the discoveries here.
A Nintendo time capsule!