While we still don't know for sure what the button does, people on ResetEra have some ideas. "Calling it now: it's C for ...
What's interesting is that the app store listing may have inadvertently revealed the mysterious and much-rumored "C" button that is supposed to be on the right-side Joy-Con controller, thanks to VGC.
Results that may be inaccessible to you are currently showing.
Hide inaccessible results