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 (this._saveInProgress) {
      return;
    }
    this._saveInProgress = true;
    await this.pdfScriptingManager.dispatchWillSave();
    const url = this.baseUrl,
      filename = this._docFilename;
    try {
      this._ensureDownloadComplete();
      const data = await this.pdfDocument.saveDocument();
      const blob = new Blob([data], { type: "application/pdf" });
      await this.downloadManager.download(blob, url, filename, sourceEventType);
    } catch (reason) {
      
      
      await this.download({ sourceEventType });
    } finally {
      await this.pdfScriptingManager.dispatchDidSave();
      this._saveInProgress = false;
    }
  },
  downloadOrSave(options) {
    if (this.pdfDocument?.annotationStorage.size > 0) {
      this.save(options);
    } else {
      this.download(options);
    }
  },
  fallback(featureId) {