On https://github.com/mozilla/pdf.js/wiki/Required-Browser-Features we mention required browser features for PDF.js, but I have the feeling that not all of them are necessary nowadays since we moved to using more modern features over the years. Moreover, as indicated in https://github.com/mozilla/pdf.js/issues/11950#issuecomment-637149085, some features may be missing such as range requests or `async/await`.

In short, we should verify which are still necessary and update the wiki page and the automated feature detection if possible.
content = preprocessor2.preprocessPDFJSCode(ctx, content);
    return babel.transform(content, {
      sourceType: "module",
      presets: undefined, 
      plugins: [
        "@babel/plugin-proposal-logical-assignment-operators",
        "@babel/plugin-transform-modules-commonjs",
        babelPluginReplaceNonWebPackRequire,
      ],
    }).code;
  }
  var babel = require("@babel/core");
  var ctx = {
    rootPath: __dirname,
    saveComments: false,
    defines: builder.merge(DEFINES, {
      GENERIC: true,
      LIB: true,
      BUNDLE_VERSION: 0, 
      BUNDLE_BUILD: 0, 
    }),
    map: {
      "pdfjs-lib": "../pdf",
    },
  };
  var preprocessor2 = require("./external/builder/preprocessor2.js");