[ihuman]

I'm surprised to see that this is on Google's Github page. Do they have any projects (besides this) that use Common Lisp?

[chaitanya]

They bought ITA Software a few years ago, which largely used Common Lisp.

[bch]

And additionally employ Peter Norvig[0].

[0] https://en.wikipedia.org/wiki/Peter_Norvig

[mapcars]

They also have a style guide: https://google.github.io/styleguide/lispguide.xml

[tsuru]

I think they also use Common Lisp with their work on D-wave quantum computers. I'd still wager the ITA group has the lion share of Lisp though.