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,
  build-depends: base == 4.*
  default-language: Haskell2010    
    -- Note whitespace after “Haskell 2010”.