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.
.pipe(gulp.dest(TYPESTEST_DIR + "build/")),
      gulp
        .src(TYPES_DIR + "**/*", { base: TYPES_DIR })
        .pipe(gulp.dest(TYPESTEST_DIR + "types/")),
    ]);
  })
);
gulp.task(
  "typestest",
  gulp.series("typestest-pre", function (done) {
    exec('"node_modules/.bin/tsc" -p test/types', function (err, stdout) {
      if (err) {
        console.log(`Couldn't compile TypeScript test: ${stdout}`);
      }
      done(err);
    });
  })
);
gulp.task("baseline", function (done) {
  console.log();
  console.log("### Creating baseline environment");
  var baselineCommit = process.env.BASELINE;
  if (!baselineCommit) {
    done(new Error("Missing baseline commit. Specify the BASELINE variable."));
    return;
  }
  var initializeCommand = "git fetch origin";
  if (!checkDir(BASELINE_DIR)) {
    mkdirp.sync(BASELINE_DIR);
    initializeCommand = "git clone ../../ .";