libghc-wai-extra-dev binary package in Ubuntu Focal amd64

 wai is a common protocol for communication between web aplications and web
 servers.
 .
 This library provides some common features not tied to a particular web
 application or web server.
 .
 This package provides a library for the Haskell programming language.
 See http://www.haskell.org/ for more information on Haskell.

Source package