In short, yes you can see the contents of an imported PDF in a lightbox.

To view the file:

1. Hover over the block and click on the eye icon that appears at the top-right corner.
2. The PDF file will be opened in a lightbox where you can scroll up and down to read it. The toolbar at the top gives you options to:
   • View the thumbnail from the left sidebar
   • Find and highlight words in PDF
   • Zoom in/out
   • Rotate the page
   • Download the file