Install libghc-happstack-authenticate-doc by entering the following commands in the terminal:
sudo apt update sudo apt install libghc-happstack-authenticate-doc
Description:
Happstack authentication library; documentation
A themeable web authentication library with support for username+password and OpenID. . This package provides the documentation for a library for the Haskell programming language. See http://www.haskell.org/ for more information on Haskell.
Homepage: http://www.happstack.com/
Version: 2.3.4.7-2build3
Section: universe/doc