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.
console.warn("Warning: JavaScript support is not enabled");
        this.fallback(UNSUPPORTED_FEATURES.javaScript);
        return true;
      });
      if (!triggerAutoPrint) {
        
        for (const js of javaScript) {
          if (js && AutoPrintRegExp.test(js)) {
            triggerAutoPrint = true;
            break;
          }
        }
      }
    }
    if (triggerAutoPrint) {
      this.triggerPrinting();
    }
  },
  /**
   * @private
   */
  async _initializeMetadata(pdfDocument) {
    const { info, metadata, contentDispositionFilename, contentLength } =
      await pdfDocument.getMetadata();
    if (pdfDocument !== this.pdfDocument) {
      return; 
    }
    this.documentInfo = info;
    this.metadata = metadata;
    this._contentDispositionFilename ??= contentDispositionFilename;