Replying to this one since you apparently can't reply to a comment that has been flagged. Why was the grandparent flagged? Google's S2 library has been around for more than a decade and is the first thing I think of when I see "S2" in a tech stack.

And the flippant response from the parent here that they don't really care that they're muddying the waters and just want the crate name is irksome.