Mobile Trainer

The Mobile Trainer is the operation software for Nintendo and Mobile21's now defunct (as of December 14, 2002) Mobile System GB service, designed for both Game Boy Color and Game Boy Advance.

The Mobile Trainer was originally planned to be released as the Mobile Starter Cartridge, but the name was later changed, perhaps to allude to Pokémon Trainers, as the Japanese Pokémon Crystal Version was one of the intended games to use it.

The Mobile Trainer was intended to be used for the combination of a peripheral known as the Mobile GB Adapter and Japanese mobile phones to connect to the World Wide Web, similar to services such as Satellaview, Randnet and its successors such as the Nintendo Network. This included games relevant to the Mario series, such as Mobile Golf and the Japanese version of Mario Kart: Super Circuit.

The Mobile Trainer's main purpose was as operation software for configuring the Game Boy Color with the user's mobile phone. However, the Mobile Trainer could also be used to connect to a limited web browser for news, and to send email between friends.

Relevance to the Mario franchise
The Mobile GB Adapter was packaged with this software, but there was also a bundle including it and Mobile Golf. Furthermore, both Mobile Golf and Mario Kart Super Circuit were advertised on the software's web browser, according to Nintendo Online Magazine.

In 2016, a dataminer with the pseudonym Háčky documented that hidden Mario related emails with an unknown purpose can be found within the code. (The other non-Mario related messages can be seen here.)