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.
preprocessCSS("web/viewer.css", "chrome", defines, true)
          .pipe(
            postcss([autoprefixer({ overrideBrowserslist: ["chrome >= 49"] })])
          )
          .pipe(gulp.dest(CHROME_BUILD_CONTENT_DIR + "web")),
        gulp.src("LICENSE").pipe(gulp.dest(CHROME_BUILD_DIR)),
        gulp
          .src("extensions/chromium/manifest.json")
          .pipe(replace(/\bPDFJSSCRIPT_VERSION\b/g, version))
          .pipe(gulp.dest(CHROME_BUILD_DIR)),
        gulp
          .src(
            [
              "extensions/chromium/**/*.{html,js,css,png}",
              "extensions/chromium/preferences_schema.json",
            ],
            { base: "extensions/chromium/" }
          )
          .pipe(gulp.dest(CHROME_BUILD_DIR)),
      ]);
    }
  )
);
gulp.task("chromium", gulp.series("chromium-pre"));
gulp.task("jsdoc", function (done) {
  console.log();
  console.log("### Generating documentation (JSDoc)");
  var JSDOC_FILES = ["src/doc_helper.js", "src/display/api.js"];
  rimraf(JSDOC_BUILD_DIR, function () {
    mkdirp(JSDOC_BUILD_DIR).then(function () {