Folks haven't used this since like 2012, no?

https://github.com/google/closure-library is being sunset in August of this year.

And here, https://developers.google.com/closure/compiler/docs/gettings...:

> Closure compiler service is deprecated, and will be removed. Please consider running the compiler locally instead.

Seems like an active project: https://github.com/google/closure-compiler

It's cool that they named a compiler after the common phenomenon :)