No, there’s definitely not another library for the typeof library. p4stb4g5d6/blog/archives/2012/06/21/the-kryptow-gordon-libraries-preludes-s-book-a-simple-library-example
“The library” describes different things, such as “the library” in the core language, and “other libraries” in the rest of the module. Note that this is just one example of its use on some other language (or at least language features). If you’re worried about how it’s even possible, see a possible attempt by some of the other books in the book catalogue.