What the author wrote is a IPython / Jupyter notebook [0], which is implemented as a JSON document [1]. The notebooks are pretty much markdown with runnable code blocks in between.
Jupyter notebooks are popular in the data science / Python communities to explain concepts, for examples see here [2].
I think it's the overall market for smart watches? For sure, it's not the next iPhone or iPad in terms of revenue.
Even in the smartwatch category, Apple isn't doing too well. Going from 70% in market share from last year to 41% this year. They're still the market leader, though.
https://en.wikipedia.org/wiki/Arvest_Bank
which is owned by the Waltons. They only seem to be in Arkansas though, which is less scalable than the entire internet.