xterm.dart/lib/util/constants.dart

const kReleaseMode = bool.fromEnvironment(
  'dart.vm.product',
  defaultValue: false,
);

const kProfileMode = bool.fromEnvironment(
  'dart.vm.profile',
  defaultValue: false,
);

const kDebugMode = !kReleaseMode && !kProfileMode;

const kIsWeb = identical(0, 0.0);