STR:
  - Go to https://mozilla.github.io/pdf.js/web/viewer.html
  - Click on "Open File" and open a pdf

The `Download` button and the `Current view` one just disappear.
I can reproduce this bug with Firefox nightly, Chrome stable and Epiphany on debian.
if (document.blockUnblockOnload) {
      document.blockUnblockOnload(false);
    }
    
    this._unblockDocumentLoadEvent = () => {};
  },
  /**
   * Used together with the integration-tests, to enable awaiting full
   * initialization of the scripting/sandbox.
   */
  get scriptingReady() {
    return this.pdfScriptingManager.ready;
  },
};
let validateFileURL;
if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
  const HOSTED_VIEWER_ORIGINS = [
    "null",
    "http://mozilla.github.io",
    "https://mozilla.github.io",
  ];
  validateFileURL = function (file) {
    if (file === undefined) {
      return;
    }
    try {
      const viewerOrigin = new URL(window.location.href).origin || "null";
      if (HOSTED_VIEWER_ORIGINS.includes(viewerOrigin)) {
        
        return;