I once created a website to catalog all of the out of copyright books in the Library of Congress and randomized selections so one could replicate the serendipit

I once created a website to catalog all of the out of copyright books in the Library of Congress and randomized selections so one could replicate the serendipity of browsing (locserendipity.com). In the process of doing this, Jessamyn West identified stickers or stamps on some of the books (https://twitter.com/jessamyn/status/1114333025716854784 https://twitter.com/jessamyn/status/1114333025716854784). Some of the staff at the LOC knew what they were—-stamps marking which books to take offsite in the the unlikely event the Nazis invaded the United States.