Nothing to do with UNIX, but a reminder that occasionally long thought
lost manuals still pop-up.

"Researchers will be able to gain a deeper understanding of what’s
considered the world’s oldest surviving (digital) computer after its
long-lost user manual was unearthed. The Z4, which was built in 1945,
runs on tape, takes up most of a room and needs several people to
operate it. The machine now takes residence at the Deutsches Museum in
Munich, but it hasn’t been used in quite some time."
https://www.engadget.com/oldest-computer-manual-zuse-z4-161214346.html