Since #12241 we have notifications for this when the user navigates away from the viewer, but we do not yet warn when switching documents, which means that if you call e.g. `PDFViewerApplication.open` with a new document (or directly call `BaseViewer.setDocument` when using the viewer components standalone) there won't be any warning about losing form data. This should be addressed.
if (PDFViewerApplication.overlayManager.active) {
    return;
  }
  let handled = false,
    ensureViewerFocused = false;
  const cmd =
    (evt.ctrlKey ? 1 : 0) |
    (evt.altKey ? 2 : 0) |
    (evt.shiftKey ? 4 : 0) |
    (evt.metaKey ? 8 : 0);
  const pdfViewer = PDFViewerApplication.pdfViewer;
  const isViewerInPresentationMode = pdfViewer?.isInPresentationMode;
  
  
  if (cmd === 1 || cmd === 8 || cmd === 5 || cmd === 12) {
    
    switch (evt.keyCode) {
      case 70: 
        if (!PDFViewerApplication.supportsIntegratedFind && !evt.shiftKey) {
          PDFViewerApplication.findBar.open();
          handled = true;
        }