It's certainly not weird for libraries to be references to the language or culture of the language itself. Not to mention that the name can refer to relevant technical details that are related to the language - for example, if a parser library uses applicative parsers, maybe the name of the library has some reference to applicative in the title.

I was referring to using this kind of terminology in more user-facing applications - for example xmonad (I don't know what monads have to do with tiling window managers. Maybe it has something to do with how the configuration library of xmonad is structured).

Admittedly, maybe Haskoin was a bad example in this regard.