I think she followed up a few years later and said that the bad situation she was in was unrelated to her leaving Github. It was mostly the time commitment of maintaining many open source projects.

What happened to the author? I'm not aware of the history...

What happened was essentially bullies. I think it is apparent now that the library and, more importantly, the idea of a data first neural network architecture in javascript isn't going away.

What do you mean by "data-first"? What other forms could a JS NN architecture take?

A lot of neural networks start by first constructing the neural network structure, and eventually getting around to running the data through it. Where in brain.js, line 2 in most examples (just after instantiation) is train with data.