In PR #13214 we implemented rendering digital signature annotations, but they are not validated yet. For mozilla-central we display the fallback bar with a clear warning that the signatures are not validated so the user is aware of this, but we have no such mechanism for the generic viewer yet.

I'm thinking we could implement something similar to the fallback bar, which might even be more generally useful for other kinds of messages we now display in the fallback bar. For mozilla-central we'd then use the current browser fallback bar, and for other targets we would display the PDF.js fallback bar instead.

Alternatively we could perhaps add a semi-transparent overlay over the signature.
this.pdfLinkService.setHash(storedHash);
    }
    
    
    this.toolbar.setPageNumber(
      this.pdfViewer.currentPageNumber,
      this.pdfViewer.currentPageLabel
    );
    this.secondaryToolbar.setPageNumber(this.pdfViewer.currentPageNumber);
    if (!this.pdfViewer.currentScaleValue) {
      
      
      this.pdfViewer.currentScaleValue = DEFAULT_SCALE_VALUE;
    }
  },
  /**
   * @private
   */
  _cleanup() {
    if (!this.pdfDocument) {
      return; 
    }
    this.pdfViewer.cleanup();
    this.pdfThumbnailViewer.cleanup();
    
    this.pdfDocument.cleanup(
       this.pdfViewer.renderer === RendererType.SVG
    );
  },
  forceRendering() {