anchor.diff:  , categories ? "Application;Other;"
   , startupNotify ? null
   , extraEntries ? null
  +, fileValidation ? true # whether to validate resulting desktop file.
   }:
   
   let
  
positive.code:     ${if extraEntries == null then ''EOF'' else ''
      ${extraEntries}
      EOF''}
    ''
  
negative.code: { lib, runCommandLocal, desktop-file-utils }:
  
  { name
  , type ? "Application"
  , exec
  