It appears that the official chrome webstore extension by Rob W is outdated. It was last updated in 2019. 

gulp.series(
    setTestEnv,
    "generic",
    "types",
    function createTypesTest() {
      return merge([
        packageJson().pipe(gulp.dest(TYPESTEST_DIR)),
        gulp
          .src([
            GENERIC_DIR + "build/pdf.js",
            GENERIC_DIR + "build/pdf.worker.js",
            SRC_DIR + "pdf.worker.entry.js",
          ])
          .pipe(gulp.dest(TYPESTEST_DIR + "build/")),
        gulp
          .src(TYPES_DIR + "**/*", { base: TYPES_DIR })
          .pipe(gulp.dest(TYPESTEST_DIR + "types/")),
      ]);
    },
    function runTypesTest(done) {
      exec('"node_modules/.bin/tsc" -p test/types', function (err, stdout) {
        if (err) {
          console.log(`Couldn't compile TypeScript test: ${stdout}`);
        }
        done(err);
      });
    }
  )
);
function createBaseline(done) {