pkg.cabal

cabal-version: 3.0
name: pkg
synopsis: synopsis
description: description
version: 0
category: example
maintainer: none@example.com
license: GPL-3.0-or-later

library
    exposed-modules: Foo,
                     Foo

--   if os(linux)
--     exposed-modules: Bar
--   if !os(linux)
--     exposed-modules: Bar

  default-language: Haskell2010