This is very confusing as seen in #12974 or #12906. My suggestion would be "legacy."
})
      .pipe(gulp.dest(dir + "web/cmaps")),
    preprocessHTML("web/viewer.html", defines).pipe(gulp.dest(dir + "web")),
    preprocessCSS("web/viewer.css", "generic", defines, true)
      .pipe(postcss([calc(), autoprefixer(AUTOPREFIXER_CONFIG)]))
      .pipe(gulp.dest(dir + "web")),
    gulp
      .src("web/compressed.tracemonkey-pldi-09.pdf")
      .pipe(gulp.dest(dir + "web")),
  ]);
}
gulp.task(
  "generic",
  gulp.series(
    "buildnumber",
    "default_preferences",
    "locale",
    function scripting() {
      var defines = builder.merge(DEFINES, { GENERIC: true });
      return createTemporaryScriptingBundle(defines);
    },
    function () {
      console.log();
      console.log("### Creating generic viewer");
      var defines = builder.merge(DEFINES, { GENERIC: true });
      return buildGeneric(defines, GENERIC_DIR);
    }
  )
);
gulp.task(