Good Haskell source to read and learn from [closed

Question

What are some open source programs that use Haskell and can be considered to be good quality modern Haskell? The larger the code base, the better.

I want to learn from their source code. I feel I'm past the point of learning from small code examples, which are often to esoteric and small-world. I want to see how code is structured, how monads interact when you have a lot of things going on (logging, I/O, configuration, etc.).

Answer 1

XMonad is an open source tiling window manager, originally loosely modeled on dwm. There are a lot of extensions, of varying quality, but the core is compact and well organized.