This seems to have been discovered after hacker Zammis Clark had blasted into Nintendo’s servers in 2018, later for which he stole private data, and pleaded guilty of performing. Elements of this information have been discharged since, and thus the source code leak’s validity appears to be tight. A supposed escape of the source code for Nintendo’s Pokémon Blue and Pokémon Yellow suggests that the release of Pokémon Yellow wasn’t intended to be the sole followup to the original two games, as traces referencing Pokémon Pink can also be observed from the code.
This also saw victory and marked a substantial step in the progress of the morale system with Pokémon that developed from the next generation of this match collection. However, source code which was leaked from 4chan’s /vp for its 2 games implies that Pokémon Pink was intended to be published alongside Pokémon Yellow, with Clefairy the likely candidate for the cover star. The first games, Pokémon Blue and Red, launched in the U.S. in late 1998 to critical acclaim. The growth of Pikachu as the mascot of this franchise came along with the accompanying anime series of the match, where Ash Ketchum chooses Pikachu as his starter, and after the achievement of both of those original games and the TV series, Pokémon Yellow launched a year after with Pikachu as the primary cover star.
Clefairy was also one of the very praised designs in the first for much the same reason that Pikachu was, harboring cuteness that led it to being a mascot that is little. However, with Pikachu proving to be a character that is far more popular, it is likely that Nintendo believed that just one follow-up was required.