Contact Print Summary - can fields be added?
It's hard to tell, but I think this is unintentional.  There's a line in the code that says to hide the first section of the contact when in print summary mode, but I suspect the "first section" used to be something else.  I can't see any reason why this should be removed.

I can tell you the quick fix, but I'll also submit this for consideration to others.

For now, you need to know how to find where CiviCRM is installed on your folder.


Inside that folder, find the file located at &lt;civiroot&gt;CRM/Contact/Page/View/Print.tpl.  This controls the print view.
Open the file and find the line (about 4 lines from the bottom) that says:


cj('#contact-summary' ).children(':first').remove();



Delete that line and save the file.


That should fix your problem! 

UPDATE: Submitted a bug report here: https://lab.civicrm.org/dev/core/issues/477