libghc-lens-doc 4.12.3-2 (amd64 binary) in ubuntu xenial

 This package comes "Batteries Included" with many useful lenses for the types
 commonly used from the Haskell Platform, and with tools for automatically
 generating lenses and isomorphisms for user-supplied data types.
 .
 The combinators in Control.Lens provide a highly generic toolbox for composing
 families of getters, folds, isomorphisms, traversals, setters and lenses and
 their indexed variants.
 .
 More information on the care and feeding of lenses, including a tutorial and
 motivation for their types can be found on the lens wiki
 (https://github.com/ekmett/lens/wiki).
 .
 This package contains the documentation files.