This is an unofficial organization. I am in no way affiliated with Nintendo.
This organization hosts the source code of various services behind https://nintendo-playground.com.
The playground lets you test custom client implementations without contacting Nintendo's servers. This can be useful because invalid requests can easily get your device banned, and buying a new one is expensive.
Here are some examples that show why custom clients can be useful:
I also wanted to practice with web technology (see infrastructure).