It was previously believed that the Z Saber Battle Chip could only be accessed by trading it into the game from Mega Man Zero 3, of which each copy of the game had only one copy of the chip. However, in 2022, an easier way to obtain the chip was discovered by entering the following hidden code at the Number Trader: 72794137. This code also works in the Japanese version of the game, causing its existence to baffle players as it has never been released in any of the game's official strategy guides. It's possible that the code was intended to be used during development as an easier way to access the chip without having to trade it across games, and that it was never meant to be found by players.
Contributed by MehDeletingLater