It’s obscure unless you’re a classical musician (or a pitch/tuning nerd): a lot more people than just piano players know of Bach’s work.
I was about to say - I took this for a Gödel, Escher, Bach reference given it's someone at Google, as well as the fact the pun is very much Hofstadter's style. In fact I would go so far as to say that the whole project was made to justify the title.
I cringed when I read the url name google chose to go with.